point of a literature review

Purdue Online Writing Lab Purdue OWL® College of Liberal Arts

Writing a Literature Review

Welcome to the Purdue OWL

This page is brought to you by the OWL at Purdue University. When printing this page, you must include the entire legal notice.

Copyright ©1995-2018 by The Writing Lab & The OWL at Purdue and Purdue University. All rights reserved. This material may not be published, reproduced, broadcast, rewritten, or redistributed without permission. Use of this site constitutes acceptance of our terms and conditions of fair use.

A literature review is a document or section of a document that collects key sources on a topic and discusses those sources in conversation with each other (also called synthesis ). The lit review is an important genre in many disciplines, not just literature (i.e., the study of works of literature such as novels and plays). When we say “literature review” or refer to “the literature,” we are talking about the research ( scholarship ) in a given field. You will often see the terms “the research,” “the scholarship,” and “the literature” used mostly interchangeably.

Where, when, and why would I write a lit review?

There are a number of different situations where you might write a literature review, each with slightly different expectations; different disciplines, too, have field-specific expectations for what a literature review is and does. For instance, in the humanities, authors might include more overt argumentation and interpretation of source material in their literature reviews, whereas in the sciences, authors are more likely to report study designs and results in their literature reviews; these differences reflect these disciplines’ purposes and conventions in scholarship. You should always look at examples from your own discipline and talk to professors or mentors in your field to be sure you understand your discipline’s conventions, for literature reviews as well as for any other genre.

A literature review can be a part of a research paper or scholarly article, usually falling after the introduction and before the research methods sections. In these cases, the lit review just needs to cover scholarship that is important to the issue you are writing about; sometimes it will also cover key sources that informed your research methodology.

Lit reviews can also be standalone pieces, either as assignments in a class or as publications. In a class, a lit review may be assigned to help students familiarize themselves with a topic and with scholarship in their field, get an idea of the other researchers working on the topic they’re interested in, find gaps in existing research in order to propose new projects, and/or develop a theoretical framework and methodology for later research. As a publication, a lit review usually is meant to help make other scholars’ lives easier by collecting and summarizing, synthesizing, and analyzing existing research on a topic. This can be especially helpful for students or scholars getting into a new research area, or for directing an entire community of scholars toward questions that have not yet been answered.

What are the parts of a lit review?

Most lit reviews use a basic introduction-body-conclusion structure; if your lit review is part of a larger paper, the introduction and conclusion pieces may be just a few sentences while you focus most of your attention on the body. If your lit review is a standalone piece, the introduction and conclusion take up more space and give you a place to discuss your goals, research methods, and conclusions separately from where you discuss the literature itself.

Introduction:

• An introductory paragraph that explains what your working topic and thesis is
• A forecast of key topics or texts that will appear in the review
• Potentially, a description of how you found sources and how you analyzed them for inclusion and discussion in the review (more often found in published, standalone literature reviews than in lit review sections in an article or research paper)
• Summarize and synthesize: Give an overview of the main points of each source and combine them into a coherent whole
• Analyze and interpret: Don’t just paraphrase other researchers – add your own interpretations where possible, discussing the significance of findings in relation to the literature as a whole
• Critically Evaluate: Mention the strengths and weaknesses of your sources
• Write in well-structured paragraphs: Use transition words and topic sentence to draw connections, comparisons, and contrasts.

Conclusion:

• Summarize the key findings you have taken from the literature and emphasize their significance
• Connect it back to your primary research question

How should I organize my lit review?

Lit reviews can take many different organizational patterns depending on what you are trying to accomplish with the review. Here are some examples:

• Chronological : The simplest approach is to trace the development of the topic over time, which helps familiarize the audience with the topic (for instance if you are introducing something that is not commonly known in your field). If you choose this strategy, be careful to avoid simply listing and summarizing sources in order. Try to analyze the patterns, turning points, and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred (as mentioned previously, this may not be appropriate in your discipline — check with a teacher or mentor if you’re unsure).
• Thematic : If you have found some recurring central themes that you will continue working with throughout your piece, you can organize your literature review into subsections that address different aspects of the topic. For example, if you are reviewing literature about women and religion, key themes can include the role of women in churches and the religious attitude towards women.
• Qualitative versus quantitative research
• Empirical versus theoretical scholarship
• Divide the research by sociological, historical, or cultural sources
• Theoretical : In many humanities articles, the literature review is the foundation for the theoretical framework. You can use it to discuss various theories, models, and definitions of key concepts. You can argue for the relevance of a specific theoretical approach or combine various theorical concepts to create a framework for your research.

What are some strategies or tips I can use while writing my lit review?

Any lit review is only as good as the research it discusses; make sure your sources are well-chosen and your research is thorough. Don’t be afraid to do more research if you discover a new thread as you’re writing. More info on the research process is available in our "Conducting Research" resources .

As you’re doing your research, create an annotated bibliography ( see our page on the this type of document ). Much of the information used in an annotated bibliography can be used also in a literature review, so you’ll be not only partially drafting your lit review as you research, but also developing your sense of the larger conversation going on among scholars, professionals, and any other stakeholders in your topic.

Usually you will need to synthesize research rather than just summarizing it. This means drawing connections between sources to create a picture of the scholarly conversation on a topic over time. Many student writers struggle to synthesize because they feel they don’t have anything to add to the scholars they are citing; here are some strategies to help you:

• It often helps to remember that the point of these kinds of syntheses is to show your readers how you understand your research, to help them read the rest of your paper.
• Writing teachers often say synthesis is like hosting a dinner party: imagine all your sources are together in a room, discussing your topic. What are they saying to each other?
• Look at the in-text citations in each paragraph. Are you citing just one source for each paragraph? This usually indicates summary only. When you have multiple sources cited in a paragraph, you are more likely to be synthesizing them (not always, but often
• Read more about synthesis here.

The most interesting literature reviews are often written as arguments (again, as mentioned at the beginning of the page, this is discipline-specific and doesn’t work for all situations). Often, the literature review is where you can establish your research as filling a particular gap or as relevant in a particular way. You have some chance to do this in your introduction in an article, but the literature review section gives a more extended opportunity to establish the conversation in the way you would like your readers to see it. You can choose the intellectual lineage you would like to be part of and whose definitions matter most to your thinking (mostly humanities-specific, but this goes for sciences as well). In addressing these points, you argue for your place in the conversation, which tends to make the lit review more compelling than a simple reporting of other sources.

What is a Literature Review? How to Write It (with Examples)

A literature review is a critical analysis and synthesis of existing research on a particular topic. It provides an overview of the current state of knowledge, identifies gaps, and highlights key findings in the literature. 1 The purpose of a literature review is to situate your own research within the context of existing scholarship, demonstrating your understanding of the topic and showing how your work contributes to the ongoing conversation in the field. Learning how to write a literature review is a critical tool for successful research. Your ability to summarize and synthesize prior research pertaining to a certain topic demonstrates your grasp on the topic of study, and assists in the learning process. 

Table of Contents

What is the purpose of literature review , a. habitat loss and species extinction: , b. range shifts and phenological changes: , c. ocean acidification and coral reefs: , d. adaptive strategies and conservation efforts: .

• Choose a Topic and Define the Research Question: 
• Decide on the Scope of Your Review: 
• Select Databases for Searches: 
• Conduct Searches and Keep Track: 
• Review the Literature: 
• Organize and Write Your Literature Review: 
• How to write a literature review faster with Paperpal? 

Frequently asked questions 

What is a literature review .

A well-conducted literature review demonstrates the researcher’s familiarity with the existing literature, establishes the context for their own research, and contributes to scholarly conversations on the topic. One of the purposes of a literature review is also to help researchers avoid duplicating previous work and ensure that their research is informed by and builds upon the existing body of knowledge.

A literature review serves several important purposes within academic and research contexts. Here are some key objectives and functions of a literature review: 2  

1. Contextualizing the Research Problem: The literature review provides a background and context for the research problem under investigation. It helps to situate the study within the existing body of knowledge. 

2. Identifying Gaps in Knowledge: By identifying gaps, contradictions, or areas requiring further research, the researcher can shape the research question and justify the significance of the study. This is crucial for ensuring that the new research contributes something novel to the field.

Find academic papers related to your research topic faster. Try Research on Paperpal

3. Understanding Theoretical and Conceptual Frameworks: Literature reviews help researchers gain an understanding of the theoretical and conceptual frameworks used in previous studies. This aids in the development of a theoretical framework for the current research. 

4. Providing Methodological Insights: Another purpose of literature reviews is that it allows researchers to learn about the methodologies employed in previous studies. This can help in choosing appropriate research methods for the current study and avoiding pitfalls that others may have encountered. 

5. Establishing Credibility: A well-conducted literature review demonstrates the researcher’s familiarity with existing scholarship, establishing their credibility and expertise in the field. It also helps in building a solid foundation for the new research. 

6. Informing Hypotheses or Research Questions: The literature review guides the formulation of hypotheses or research questions by highlighting relevant findings and areas of uncertainty in existing literature. 

Literature review example 

Let’s delve deeper with a literature review example: Let’s say your literature review is about the impact of climate change on biodiversity. You might format your literature review into sections such as the effects of climate change on habitat loss and species extinction, phenological changes, and marine biodiversity. Each section would then summarize and analyze relevant studies in those areas, highlighting key findings and identifying gaps in the research. The review would conclude by emphasizing the need for further research on specific aspects of the relationship between climate change and biodiversity. The following literature review template provides a glimpse into the recommended literature review structure and content, demonstrating how research findings are organized around specific themes within a broader topic. 

Literature Review on Climate Change Impacts on Biodiversity:  

Climate change is a global phenomenon with far-reaching consequences, including significant impacts on biodiversity. This literature review synthesizes key findings from various studies: 

Climate change-induced alterations in temperature and precipitation patterns contribute to habitat loss, affecting numerous species (Thomas et al., 2004). The review discusses how these changes increase the risk of extinction, particularly for species with specific habitat requirements. 

Observations of range shifts and changes in the timing of biological events (phenology) are documented in response to changing climatic conditions (Parmesan & Yohe, 2003). These shifts affect ecosystems and may lead to mismatches between species and their resources. 

The review explores the impact of climate change on marine biodiversity, emphasizing ocean acidification’s threat to coral reefs (Hoegh-Guldberg et al., 2007). Changes in pH levels negatively affect coral calcification, disrupting the delicate balance of marine ecosystems. 

Recognizing the urgency of the situation, the literature review discusses various adaptive strategies adopted by species and conservation efforts aimed at mitigating the impacts of climate change on biodiversity (Hannah et al., 2007). It emphasizes the importance of interdisciplinary approaches for effective conservation planning. 

Strengthen your literature review with factual insights. Try Research on Paperpal for free!

How to write a good literature review 

Writing a literature review involves summarizing and synthesizing existing research on a particular topic. A good literature review format should include the following elements. 

Introduction: The introduction sets the stage for your literature review, providing context and introducing the main focus of your review. 

• Opening Statement: Begin with a general statement about the broader topic and its significance in the field. 
• Scope and Purpose: Clearly define the scope of your literature review. Explain the specific research question or objective you aim to address. 
• Organizational Framework: Briefly outline the structure of your literature review, indicating how you will categorize and discuss the existing research. 
• Significance of the Study: Highlight why your literature review is important and how it contributes to the understanding of the chosen topic. 
• Thesis Statement: Conclude the introduction with a concise thesis statement that outlines the main argument or perspective you will develop in the body of the literature review. 

Body: The body of the literature review is where you provide a comprehensive analysis of existing literature, grouping studies based on themes, methodologies, or other relevant criteria. 

• Organize by Theme or Concept: Group studies that share common themes, concepts, or methodologies. Discuss each theme or concept in detail, summarizing key findings and identifying gaps or areas of disagreement. 
• Critical Analysis: Evaluate the strengths and weaknesses of each study. Discuss the methodologies used, the quality of evidence, and the overall contribution of each work to the understanding of the topic. 
• Synthesis of Findings: Synthesize the information from different studies to highlight trends, patterns, or areas of consensus in the literature. 
• Identification of Gaps: Discuss any gaps or limitations in the existing research and explain how your review contributes to filling these gaps. 
• Transition between Sections: Provide smooth transitions between different themes or concepts to maintain the flow of your literature review. 

Write and Cite as yo u go with Paperpal Research. Start now for free!

Conclusion: The conclusion of your literature review should summarize the main findings, highlight the contributions of the review, and suggest avenues for future research. 

• Summary of Key Findings: Recap the main findings from the literature and restate how they contribute to your research question or objective. 
• Contributions to the Field: Discuss the overall contribution of your literature review to the existing knowledge in the field. 
• Implications and Applications: Explore the practical implications of the findings and suggest how they might impact future research or practice. 
• Recommendations for Future Research: Identify areas that require further investigation and propose potential directions for future research in the field. 
• Final Thoughts: Conclude with a final reflection on the importance of your literature review and its relevance to the broader academic community. 

Conducting a literature review 

Conducting a literature review is an essential step in research that involves reviewing and analyzing existing literature on a specific topic. It’s important to know how to do a literature review effectively, so here are the steps to follow: 1  

Choose a Topic and Define the Research Question:  

• Select a topic that is relevant to your field of study. 
• Clearly define your research question or objective. Determine what specific aspect of the topic do you want to explore? 

Decide on the Scope of Your Review:  

• Determine the timeframe for your literature review. Are you focusing on recent developments, or do you want a historical overview? 
• Consider the geographical scope. Is your review global, or are you focusing on a specific region? 
• Define the inclusion and exclusion criteria. What types of sources will you include? Are there specific types of studies or publications you will exclude? 

Select Databases for Searches:  

• Identify relevant databases for your field. Examples include PubMed, IEEE Xplore, Scopus, Web of Science, and Google Scholar. 
• Consider searching in library catalogs, institutional repositories, and specialized databases related to your topic. 

Conduct Searches and Keep Track:  

• Develop a systematic search strategy using keywords, Boolean operators (AND, OR, NOT), and other search techniques. 
• Record and document your search strategy for transparency and replicability. 
• Keep track of the articles, including publication details, abstracts, and links. Use citation management tools like EndNote, Zotero, or Mendeley to organize your references. 

Review the Literature:  

• Evaluate the relevance and quality of each source. Consider the methodology, sample size, and results of studies. 
• Organize the literature by themes or key concepts. Identify patterns, trends, and gaps in the existing research. 
• Summarize key findings and arguments from each source. Compare and contrast different perspectives. 
• Identify areas where there is a consensus in the literature and where there are conflicting opinions. 
• Provide critical analysis and synthesis of the literature. What are the strengths and weaknesses of existing research? 

Organize and Write Your Literature Review:  

• Literature review outline should be based on themes, chronological order, or methodological approaches. 
• Write a clear and coherent narrative that synthesizes the information gathered. 
• Use proper citations for each source and ensure consistency in your citation style (APA, MLA, Chicago, etc.). 
• Conclude your literature review by summarizing key findings, identifying gaps, and suggesting areas for future research. 

Whether you’re exploring a new research field or finding new angles to develop an existing topic, sifting through hundreds of papers can take more time than you have to spare. But what if you could find science-backed insights with verified citations in seconds? That’s the power of Paperpal’s new Research feature!  

How to write a literature review faster with Paperpal?  

Paperpal, an AI writing assistant, integrates powerful academic search capabilities within its writing platform. With the Research | Cite feature, you get 100% factual insights, with citations backed by 250M+ verified research articles, directly within your writing interface. It also allows you auto-cite references in 10,000+ styles and save relevant references in your Citation Library. By eliminating the need to switch tabs to find answers to all your research questions, Paperpal saves time and helps you stay focused on your writing.   

Here’s how to use the Research feature:  

• Ask a question: Get started with a new document on paperpal.com. Click on the “Research | Cite” feature and type your question in plain English. Paperpal will scour over 250 million research articles, including conference papers and preprints, to provide you with accurate insights and citations. 

• Review and Save: Paperpal summarizes the information, while citing sources and listing relevant reads. You can quickly scan the results to identify relevant references and save these directly to your built-in citations library for later access. 
• Cite with Confidence: Paperpal makes it easy to incorporate relevant citations and references in 10,000+ styles into your writing, ensuring your arguments are well-supported by credible sources. This translates to a polished, well-researched literature review. 

The literature review sample and detailed advice on writing and conducting a review will help you produce a well-structured report. But remember that a good literature review is an ongoing process, and it may be necessary to revisit and update it as your research progresses. By combining effortless research with an easy citation process, Paperpal Research streamlines the literature review process and empowers you to write faster and with more confidence. Try Paperpal Research now and see for yourself.  

A literature review is a critical and comprehensive analysis of existing literature (published and unpublished works) on a specific topic or research question and provides a synthesis of the current state of knowledge in a particular field. A well-conducted literature review is crucial for researchers to build upon existing knowledge, avoid duplication of efforts, and contribute to the advancement of their field. It also helps researchers situate their work within a broader context and facilitates the development of a sound theoretical and conceptual framework for their studies.

Literature review is a crucial component of research writing, providing a solid background for a research paper’s investigation. The aim is to keep professionals up to date by providing an understanding of ongoing developments within a specific field, including research methods, and experimental techniques used in that field, and present that knowledge in the form of a written report. Also, the depth and breadth of the literature review emphasizes the credibility of the scholar in his or her field.  

Before writing a literature review, it’s essential to undertake several preparatory steps to ensure that your review is well-researched, organized, and focused. This includes choosing a topic of general interest to you and doing exploratory research on that topic, writing an annotated bibliography, and noting major points, especially those that relate to the position you have taken on the topic. 

Literature reviews and academic research papers are essential components of scholarly work but serve different purposes within the academic realm. 3 A literature review aims to provide a foundation for understanding the current state of research on a particular topic, identify gaps or controversies, and lay the groundwork for future research. Therefore, it draws heavily from existing academic sources, including books, journal articles, and other scholarly publications. In contrast, an academic research paper aims to present new knowledge, contribute to the academic discourse, and advance the understanding of a specific research question. Therefore, it involves a mix of existing literature (in the introduction and literature review sections) and original data or findings obtained through research methods. 

Literature reviews are essential components of academic and research papers, and various strategies can be employed to conduct them effectively. If you want to know how to write a literature review for a research paper, here are four common approaches that are often used by researchers.  Chronological Review: This strategy involves organizing the literature based on the chronological order of publication. It helps to trace the development of a topic over time, showing how ideas, theories, and research have evolved.  Thematic Review: Thematic reviews focus on identifying and analyzing themes or topics that cut across different studies. Instead of organizing the literature chronologically, it is grouped by key themes or concepts, allowing for a comprehensive exploration of various aspects of the topic.  Methodological Review: This strategy involves organizing the literature based on the research methods employed in different studies. It helps to highlight the strengths and weaknesses of various methodologies and allows the reader to evaluate the reliability and validity of the research findings.  Theoretical Review: A theoretical review examines the literature based on the theoretical frameworks used in different studies. This approach helps to identify the key theories that have been applied to the topic and assess their contributions to the understanding of the subject.  It’s important to note that these strategies are not mutually exclusive, and a literature review may combine elements of more than one approach. The choice of strategy depends on the research question, the nature of the literature available, and the goals of the review. Additionally, other strategies, such as integrative reviews or systematic reviews, may be employed depending on the specific requirements of the research.

The literature review format can vary depending on the specific publication guidelines. However, there are some common elements and structures that are often followed. Here is a general guideline for the format of a literature review:  Introduction:   Provide an overview of the topic.  Define the scope and purpose of the literature review.  State the research question or objective.  Body:   Organize the literature by themes, concepts, or chronology.  Critically analyze and evaluate each source.  Discuss the strengths and weaknesses of the studies.  Highlight any methodological limitations or biases.  Identify patterns, connections, or contradictions in the existing research.  Conclusion:   Summarize the key points discussed in the literature review.  Highlight the research gap.  Address the research question or objective stated in the introduction.  Highlight the contributions of the review and suggest directions for future research.

Both annotated bibliographies and literature reviews involve the examination of scholarly sources. While annotated bibliographies focus on individual sources with brief annotations, literature reviews provide a more in-depth, integrated, and comprehensive analysis of existing literature on a specific topic. The key differences are as follows: 

References 

• Denney, A. S., & Tewksbury, R. (2013). How to write a literature review.  Journal of criminal justice education ,  24 (2), 218-234. 
• Pan, M. L. (2016).  Preparing literature reviews: Qualitative and quantitative approaches . Taylor & Francis. 
• Cantero, C. (2019). How to write a literature review.  San José State University Writing Center . 

Paperpal is a comprehensive AI writing toolkit that helps students and researchers achieve 2x the writing in half the time. It leverages 22+ years of STM experience and insights from millions of research articles to provide in-depth academic writing, language editing, and submission readiness support to help you write better, faster.  

Get accurate academic translations, rewriting support, grammar checks, vocabulary suggestions, and generative AI assistance that delivers human precision at machine speed. Try for free or upgrade to Paperpal Prime starting at US$19 a month to access premium features, including consistency, plagiarism, and 30+ submission readiness checks to help you succeed.  

Experience the future of academic writing – Sign up to Paperpal and start writing for free!  

Related Reads:

• Empirical Research: A Comprehensive Guide for Academics 
• How to Write a Scientific Paper in 10 Steps 
• How Long Should a Chapter Be?
• How to Use Paperpal to Generate Emails & Cover Letters?

6 Tips for Post-Doc Researchers to Take Their Career to the Next Level

Self-plagiarism in research: what it is and how to avoid it, you may also like, how to make a graphical abstract, academic integrity vs academic dishonesty: types & examples, dissertation printing and binding | types & comparison , what is a dissertation preface definition and examples , the ai revolution: authors’ role in upholding academic..., the future of academia: how ai tools are..., how to write a research proposal: (with examples..., how to write your research paper in apa..., how to choose a dissertation topic, how to write a phd research proposal.

• Link to facebook
• Link to linkedin
• Link to twitter
• Link to youtube
• Writing Tips

What is the Purpose of a Literature Review?

4-minute read

• 23rd October 2023

If you’re writing a research paper or dissertation , then you’ll most likely need to include a comprehensive literature review . In this post, we’ll review the purpose of literature reviews, why they are so significant, and the specific elements to include in one. Literature reviews can:

1. Provide a foundation for current research.

2. Define key concepts and theories.

3. Demonstrate critical evaluation.

4. Show how research and methodologies have evolved.

5. Identify gaps in existing research.

6. Support your argument.

Keep reading to enter the exciting world of literature reviews!

What is a Literature Review?

A literature review is a critical summary and evaluation of the existing research (e.g., academic journal articles and books) on a specific topic. It is typically included as a separate section or chapter of a research paper or dissertation, serving as a contextual framework for a study. Literature reviews can vary in length depending on the subject and nature of the study, with most being about equal length to other sections or chapters included in the paper. Essentially, the literature review highlights previous studies in the context of your research and summarizes your insights in a structured, organized format. Next, let’s look at the overall purpose of a literature review.

Find this useful?

Subscribe to our newsletter and get writing tips from our editors straight to your inbox.

Literature reviews are considered an integral part of research across most academic subjects and fields. The primary purpose of a literature review in your study is to:

Provide a Foundation for Current Research

Since the literature review provides a comprehensive evaluation of the existing research, it serves as a solid foundation for your current study. It’s a way to contextualize your work and show how your research fits into the broader landscape of your specific area of study.  

Define Key Concepts and Theories

The literature review highlights the central theories and concepts that have arisen from previous research on your chosen topic. It gives your readers a more thorough understanding of the background of your study and why your research is particularly significant .

Demonstrate Critical Evaluation 

A comprehensive literature review shows your ability to critically analyze and evaluate a broad range of source material. And since you’re considering and acknowledging the contribution of key scholars alongside your own, it establishes your own credibility and knowledge.

Show How Research and Methodologies Have Evolved

Another purpose of literature reviews is to provide a historical perspective and demonstrate how research and methodologies have changed over time, especially as data collection methods and technology have advanced. And studying past methodologies allows you, as the researcher, to understand what did and did not work and apply that knowledge to your own research.  

Identify Gaps in Existing Research

Besides discussing current research and methodologies, the literature review should also address areas that are lacking in the existing literature. This helps further demonstrate the relevance of your own research by explaining why your study is necessary to fill the gaps.

Support Your Argument

A good literature review should provide evidence that supports your research questions and hypothesis. For example, your study may show that your research supports existing theories or builds on them in some way. Referencing previous related studies shows your work is grounded in established research and will ultimately be a contribution to the field.  

Literature Review Editing Services 

Ensure your literature review is polished and ready for submission by having it professionally proofread and edited by our expert team. Our literature review editing services will help your research stand out and make an impact. Not convinced yet? Send in your free sample today and see for yourself! 

Share this article:

Post A New Comment

Got content that needs a quick turnaround? Let us polish your work. Explore our editorial business services.

5-minute read

Free Email Newsletter Template

Promoting a brand means sharing valuable insights to connect more deeply with your audience, and...

6-minute read

How to Write a Nonprofit Grant Proposal

If you’re seeking funding to support your charitable endeavors as a nonprofit organization, you’ll need...

9-minute read

How to Use Infographics to Boost Your Presentation

Is your content getting noticed? Capturing and maintaining an audience’s attention is a challenge when...

8-minute read

Why Interactive PDFs Are Better for Engagement

Are you looking to enhance engagement and captivate your audience through your professional documents? Interactive...

7-minute read

Seven Key Strategies for Voice Search Optimization

Voice search optimization is rapidly shaping the digital landscape, requiring content professionals to adapt their...

Five Creative Ways to Showcase Your Digital Portfolio

Are you a creative freelancer looking to make a lasting impression on potential clients or...

Make sure your writing is the best it can be with our expert English proofreading and editing.

• UConn Library
• Literature Review: The What, Why and How-to Guide
• Introduction

Literature Review: The What, Why and How-to Guide — Introduction

• Getting Started
• How to Pick a Topic
• Strategies to Find Sources
• Evaluating Sources & Lit. Reviews
• Tips for Writing Literature Reviews
• Writing Literature Review: Useful Sites
• Citation Resources
• Other Academic Writings

What are Literature Reviews?

So, what is a literature review? "A literature review is an account of what has been published on a topic by accredited scholars and researchers. In writing the literature review, your purpose is to convey to your reader what knowledge and ideas have been established on a topic, and what their strengths and weaknesses are. As a piece of writing, the literature review must be defined by a guiding concept (e.g., your research objective, the problem or issue you are discussing, or your argumentative thesis). It is not just a descriptive list of the material available, or a set of summaries." Taylor, D.  The literature review: A few tips on conducting it . University of Toronto Health Sciences Writing Centre.

Goals of Literature Reviews

What are the goals of creating a Literature Review?  A literature could be written to accomplish different aims:

• To develop a theory or evaluate an existing theory
• To summarize the historical or existing state of a research topic
• Identify a problem in a field of research 

Baumeister, R. F., & Leary, M. R. (1997). Writing narrative literature reviews .  Review of General Psychology , 1 (3), 311-320.

What kinds of sources require a Literature Review?

• A research paper assigned in a course
• A thesis or dissertation
• A grant proposal
• An article intended for publication in a journal

All these instances require you to collect what has been written about your research topic so that you can demonstrate how your own research sheds new light on the topic.

Types of Literature Reviews

What kinds of literature reviews are written?

Narrative review: The purpose of this type of review is to describe the current state of the research on a specific topic/research and to offer a critical analysis of the literature reviewed. Studies are grouped by research/theoretical categories, and themes and trends, strengths and weakness, and gaps are identified. The review ends with a conclusion section which summarizes the findings regarding the state of the research of the specific study, the gaps identify and if applicable, explains how the author's research will address gaps identify in the review and expand the knowledge on the topic reviewed.

• Example : Predictors and Outcomes of U.S. Quality Maternity Leave: A Review and Conceptual Framework:  10.1177/08948453211037398  

Systematic review : "The authors of a systematic review use a specific procedure to search the research literature, select the studies to include in their review, and critically evaluate the studies they find." (p. 139). Nelson, L. K. (2013). Research in Communication Sciences and Disorders . Plural Publishing.

• Example : The effect of leave policies on increasing fertility: a systematic review:  10.1057/s41599-022-01270-w

Meta-analysis : "Meta-analysis is a method of reviewing research findings in a quantitative fashion by transforming the data from individual studies into what is called an effect size and then pooling and analyzing this information. The basic goal in meta-analysis is to explain why different outcomes have occurred in different studies." (p. 197). Roberts, M. C., & Ilardi, S. S. (2003). Handbook of Research Methods in Clinical Psychology . Blackwell Publishing.

• Example : Employment Instability and Fertility in Europe: A Meta-Analysis:  10.1215/00703370-9164737

Meta-synthesis : "Qualitative meta-synthesis is a type of qualitative study that uses as data the findings from other qualitative studies linked by the same or related topic." (p.312). Zimmer, L. (2006). Qualitative meta-synthesis: A question of dialoguing with texts .  Journal of Advanced Nursing , 53 (3), 311-318.

• Example : Women’s perspectives on career successes and barriers: A qualitative meta-synthesis:  10.1177/05390184221113735

Literature Reviews in the Health Sciences

• UConn Health subject guide on systematic reviews Explanation of the different review types used in health sciences literature as well as tools to help you find the right review type
• << Previous: Getting Started
• Next: How to Pick a Topic >>
• Last Updated: Sep 21, 2022 2:16 PM
• URL: https://guides.lib.uconn.edu/literaturereview

Literature Reviews

What this handout is about.

This handout will explain what literature reviews are and offer insights into the form and construction of literature reviews in the humanities, social sciences, and sciences.

Introduction

OK. You’ve got to write a literature review. You dust off a novel and a book of poetry, settle down in your chair, and get ready to issue a “thumbs up” or “thumbs down” as you leaf through the pages. “Literature review” done. Right?

Wrong! The “literature” of a literature review refers to any collection of materials on a topic, not necessarily the great literary texts of the world. “Literature” could be anything from a set of government pamphlets on British colonial methods in Africa to scholarly articles on the treatment of a torn ACL. And a review does not necessarily mean that your reader wants you to give your personal opinion on whether or not you liked these sources.

What is a literature review, then?

A literature review discusses published information in a particular subject area, and sometimes information in a particular subject area within a certain time period.

A literature review can be just a simple summary of the sources, but it usually has an organizational pattern and combines both summary and synthesis. A summary is a recap of the important information of the source, but a synthesis is a re-organization, or a reshuffling, of that information. It might give a new interpretation of old material or combine new with old interpretations. Or it might trace the intellectual progression of the field, including major debates. And depending on the situation, the literature review may evaluate the sources and advise the reader on the most pertinent or relevant.

But how is a literature review different from an academic research paper?

The main focus of an academic research paper is to develop a new argument, and a research paper is likely to contain a literature review as one of its parts. In a research paper, you use the literature as a foundation and as support for a new insight that you contribute. The focus of a literature review, however, is to summarize and synthesize the arguments and ideas of others without adding new contributions.

Why do we write literature reviews?

Literature reviews provide you with a handy guide to a particular topic. If you have limited time to conduct research, literature reviews can give you an overview or act as a stepping stone. For professionals, they are useful reports that keep them up to date with what is current in the field. For scholars, the depth and breadth of the literature review emphasizes the credibility of the writer in his or her field. Literature reviews also provide a solid background for a research paper’s investigation. Comprehensive knowledge of the literature of the field is essential to most research papers.

Who writes these things, anyway?

Literature reviews are written occasionally in the humanities, but mostly in the sciences and social sciences; in experiment and lab reports, they constitute a section of the paper. Sometimes a literature review is written as a paper in itself.

Let’s get to it! What should I do before writing the literature review?

If your assignment is not very specific, seek clarification from your instructor:

• Roughly how many sources should you include?
• What types of sources (books, journal articles, websites)?
• Should you summarize, synthesize, or critique your sources by discussing a common theme or issue?
• Should you evaluate your sources?
• Should you provide subheadings and other background information, such as definitions and/or a history?

Find models

Look for other literature reviews in your area of interest or in the discipline and read them to get a sense of the types of themes you might want to look for in your own research or ways to organize your final review. You can simply put the word “review” in your search engine along with your other topic terms to find articles of this type on the Internet or in an electronic database. The bibliography or reference section of sources you’ve already read are also excellent entry points into your own research.

Narrow your topic

There are hundreds or even thousands of articles and books on most areas of study. The narrower your topic, the easier it will be to limit the number of sources you need to read in order to get a good survey of the material. Your instructor will probably not expect you to read everything that’s out there on the topic, but you’ll make your job easier if you first limit your scope.

Keep in mind that UNC Libraries have research guides and to databases relevant to many fields of study. You can reach out to the subject librarian for a consultation: https://library.unc.edu/support/consultations/ .

And don’t forget to tap into your professor’s (or other professors’) knowledge in the field. Ask your professor questions such as: “If you had to read only one book from the 90’s on topic X, what would it be?” Questions such as this help you to find and determine quickly the most seminal pieces in the field.

Consider whether your sources are current

Some disciplines require that you use information that is as current as possible. In the sciences, for instance, treatments for medical problems are constantly changing according to the latest studies. Information even two years old could be obsolete. However, if you are writing a review in the humanities, history, or social sciences, a survey of the history of the literature may be what is needed, because what is important is how perspectives have changed through the years or within a certain time period. Try sorting through some other current bibliographies or literature reviews in the field to get a sense of what your discipline expects. You can also use this method to consider what is currently of interest to scholars in this field and what is not.

Strategies for writing the literature review

Find a focus.

A literature review, like a term paper, is usually organized around ideas, not the sources themselves as an annotated bibliography would be organized. This means that you will not just simply list your sources and go into detail about each one of them, one at a time. No. As you read widely but selectively in your topic area, consider instead what themes or issues connect your sources together. Do they present one or different solutions? Is there an aspect of the field that is missing? How well do they present the material and do they portray it according to an appropriate theory? Do they reveal a trend in the field? A raging debate? Pick one of these themes to focus the organization of your review.

Convey it to your reader

A literature review may not have a traditional thesis statement (one that makes an argument), but you do need to tell readers what to expect. Try writing a simple statement that lets the reader know what is your main organizing principle. Here are a couple of examples:

The current trend in treatment for congestive heart failure combines surgery and medicine. More and more cultural studies scholars are accepting popular media as a subject worthy of academic consideration.

Consider organization

You’ve got a focus, and you’ve stated it clearly and directly. Now what is the most effective way of presenting the information? What are the most important topics, subtopics, etc., that your review needs to include? And in what order should you present them? Develop an organization for your review at both a global and local level:

First, cover the basic categories

Just like most academic papers, literature reviews also must contain at least three basic elements: an introduction or background information section; the body of the review containing the discussion of sources; and, finally, a conclusion and/or recommendations section to end the paper. The following provides a brief description of the content of each:

• Introduction: Gives a quick idea of the topic of the literature review, such as the central theme or organizational pattern.
• Body: Contains your discussion of sources and is organized either chronologically, thematically, or methodologically (see below for more information on each).
• Conclusions/Recommendations: Discuss what you have drawn from reviewing literature so far. Where might the discussion proceed?

Organizing the body

Once you have the basic categories in place, then you must consider how you will present the sources themselves within the body of your paper. Create an organizational method to focus this section even further.

To help you come up with an overall organizational framework for your review, consider the following scenario:

You’ve decided to focus your literature review on materials dealing with sperm whales. This is because you’ve just finished reading Moby Dick, and you wonder if that whale’s portrayal is really real. You start with some articles about the physiology of sperm whales in biology journals written in the 1980’s. But these articles refer to some British biological studies performed on whales in the early 18th century. So you check those out. Then you look up a book written in 1968 with information on how sperm whales have been portrayed in other forms of art, such as in Alaskan poetry, in French painting, or on whale bone, as the whale hunters in the late 19th century used to do. This makes you wonder about American whaling methods during the time portrayed in Moby Dick, so you find some academic articles published in the last five years on how accurately Herman Melville portrayed the whaling scene in his novel.

Now consider some typical ways of organizing the sources into a review:

• Chronological: If your review follows the chronological method, you could write about the materials above according to when they were published. For instance, first you would talk about the British biological studies of the 18th century, then about Moby Dick, published in 1851, then the book on sperm whales in other art (1968), and finally the biology articles (1980s) and the recent articles on American whaling of the 19th century. But there is relatively no continuity among subjects here. And notice that even though the sources on sperm whales in other art and on American whaling are written recently, they are about other subjects/objects that were created much earlier. Thus, the review loses its chronological focus.
• By publication: Order your sources by publication chronology, then, only if the order demonstrates a more important trend. For instance, you could order a review of literature on biological studies of sperm whales if the progression revealed a change in dissection practices of the researchers who wrote and/or conducted the studies.
• By trend: A better way to organize the above sources chronologically is to examine the sources under another trend, such as the history of whaling. Then your review would have subsections according to eras within this period. For instance, the review might examine whaling from pre-1600-1699, 1700-1799, and 1800-1899. Under this method, you would combine the recent studies on American whaling in the 19th century with Moby Dick itself in the 1800-1899 category, even though the authors wrote a century apart.
• Thematic: Thematic reviews of literature are organized around a topic or issue, rather than the progression of time. However, progression of time may still be an important factor in a thematic review. For instance, the sperm whale review could focus on the development of the harpoon for whale hunting. While the study focuses on one topic, harpoon technology, it will still be organized chronologically. The only difference here between a “chronological” and a “thematic” approach is what is emphasized the most: the development of the harpoon or the harpoon technology.But more authentic thematic reviews tend to break away from chronological order. For instance, a thematic review of material on sperm whales might examine how they are portrayed as “evil” in cultural documents. The subsections might include how they are personified, how their proportions are exaggerated, and their behaviors misunderstood. A review organized in this manner would shift between time periods within each section according to the point made.
• Methodological: A methodological approach differs from the two above in that the focusing factor usually does not have to do with the content of the material. Instead, it focuses on the “methods” of the researcher or writer. For the sperm whale project, one methodological approach would be to look at cultural differences between the portrayal of whales in American, British, and French art work. Or the review might focus on the economic impact of whaling on a community. A methodological scope will influence either the types of documents in the review or the way in which these documents are discussed. Once you’ve decided on the organizational method for the body of the review, the sections you need to include in the paper should be easy to figure out. They should arise out of your organizational strategy. In other words, a chronological review would have subsections for each vital time period. A thematic review would have subtopics based upon factors that relate to the theme or issue.

Sometimes, though, you might need to add additional sections that are necessary for your study, but do not fit in the organizational strategy of the body. What other sections you include in the body is up to you. Put in only what is necessary. Here are a few other sections you might want to consider:

• Current Situation: Information necessary to understand the topic or focus of the literature review.
• History: The chronological progression of the field, the literature, or an idea that is necessary to understand the literature review, if the body of the literature review is not already a chronology.
• Methods and/or Standards: The criteria you used to select the sources in your literature review or the way in which you present your information. For instance, you might explain that your review includes only peer-reviewed articles and journals.

Questions for Further Research: What questions about the field has the review sparked? How will you further your research as a result of the review?

Begin composing

Once you’ve settled on a general pattern of organization, you’re ready to write each section. There are a few guidelines you should follow during the writing stage as well. Here is a sample paragraph from a literature review about sexism and language to illuminate the following discussion:

However, other studies have shown that even gender-neutral antecedents are more likely to produce masculine images than feminine ones (Gastil, 1990). Hamilton (1988) asked students to complete sentences that required them to fill in pronouns that agreed with gender-neutral antecedents such as “writer,” “pedestrian,” and “persons.” The students were asked to describe any image they had when writing the sentence. Hamilton found that people imagined 3.3 men to each woman in the masculine “generic” condition and 1.5 men per woman in the unbiased condition. Thus, while ambient sexism accounted for some of the masculine bias, sexist language amplified the effect. (Source: Erika Falk and Jordan Mills, “Why Sexist Language Affects Persuasion: The Role of Homophily, Intended Audience, and Offense,” Women and Language19:2).

Use evidence

In the example above, the writers refer to several other sources when making their point. A literature review in this sense is just like any other academic research paper. Your interpretation of the available sources must be backed up with evidence to show that what you are saying is valid.

Be selective

Select only the most important points in each source to highlight in the review. The type of information you choose to mention should relate directly to the review’s focus, whether it is thematic, methodological, or chronological.

Use quotes sparingly

Falk and Mills do not use any direct quotes. That is because the survey nature of the literature review does not allow for in-depth discussion or detailed quotes from the text. Some short quotes here and there are okay, though, if you want to emphasize a point, or if what the author said just cannot be rewritten in your own words. Notice that Falk and Mills do quote certain terms that were coined by the author, not common knowledge, or taken directly from the study. But if you find yourself wanting to put in more quotes, check with your instructor.

Summarize and synthesize

Remember to summarize and synthesize your sources within each paragraph as well as throughout the review. The authors here recapitulate important features of Hamilton’s study, but then synthesize it by rephrasing the study’s significance and relating it to their own work.

Keep your own voice

While the literature review presents others’ ideas, your voice (the writer’s) should remain front and center. Notice that Falk and Mills weave references to other sources into their own text, but they still maintain their own voice by starting and ending the paragraph with their own ideas and their own words. The sources support what Falk and Mills are saying.

Use caution when paraphrasing

When paraphrasing a source that is not your own, be sure to represent the author’s information or opinions accurately and in your own words. In the preceding example, Falk and Mills either directly refer in the text to the author of their source, such as Hamilton, or they provide ample notation in the text when the ideas they are mentioning are not their own, for example, Gastil’s. For more information, please see our handout on plagiarism .

Revise, revise, revise

Draft in hand? Now you’re ready to revise. Spending a lot of time revising is a wise idea, because your main objective is to present the material, not the argument. So check over your review again to make sure it follows the assignment and/or your outline. Then, just as you would for most other academic forms of writing, rewrite or rework the language of your review so that you’ve presented your information in the most concise manner possible. Be sure to use terminology familiar to your audience; get rid of unnecessary jargon or slang. Finally, double check that you’ve documented your sources and formatted the review appropriately for your discipline. For tips on the revising and editing process, see our handout on revising drafts .

Works consulted

We consulted these works while writing this handout. This is not a comprehensive list of resources on the handout’s topic, and we encourage you to do your own research to find additional publications. Please do not use this list as a model for the format of your own reference list, as it may not match the citation style you are using. For guidance on formatting citations, please see the UNC Libraries citation tutorial . We revise these tips periodically and welcome feedback.

Anson, Chris M., and Robert A. Schwegler. 2010. The Longman Handbook for Writers and Readers , 6th ed. New York: Longman.

Jones, Robert, Patrick Bizzaro, and Cynthia Selfe. 1997. The Harcourt Brace Guide to Writing in the Disciplines . New York: Harcourt Brace.

Lamb, Sandra E. 1998. How to Write It: A Complete Guide to Everything You’ll Ever Write . Berkeley: Ten Speed Press.

Rosen, Leonard J., and Laurence Behrens. 2003. The Allyn & Bacon Handbook , 5th ed. New York: Longman.

Troyka, Lynn Quittman, and Doug Hesse. 2016. Simon and Schuster Handbook for Writers , 11th ed. London: Pearson.

You may reproduce it for non-commercial use if you use the entire handout and attribute the source: The Writing Center, University of North Carolina at Chapel Hill

Make a Gift

Harvey Cushing/John Hay Whitney Medical Library

• Collections
• Research Help

YSN Doctoral Programs: Steps in Conducting a Literature Review

• Biomedical Databases
• Global (Public Health) Databases
• Soc. Sci., History, and Law Databases
• Grey Literature
• Trials Registers
• Data and Statistics
• Public Policy
• Google Tips
• Recommended Books
• Steps in Conducting a Literature Review

What is a literature review?

A literature review is an integrated analysis -- not just a summary-- of scholarly writings and other relevant evidence related directly to your research question.  That is, it represents a synthesis of the evidence that provides background information on your topic and shows a association between the evidence and your research question.

A literature review may be a stand alone work or the introduction to a larger research paper, depending on the assignment.  Rely heavily on the guidelines your instructor has given you.

Why is it important?

A literature review is important because it:

• Explains the background of research on a topic.
• Demonstrates why a topic is significant to a subject area.
• Discovers relationships between research studies/ideas.
• Identifies major themes, concepts, and researchers on a topic.
• Identifies critical gaps and points of disagreement.
• Discusses further research questions that logically come out of the previous studies.

APA7 Style resources

APA Style Blog - for those harder to find answers

1. Choose a topic. Define your research question.

Your literature review should be guided by your central research question.  The literature represents background and research developments related to a specific research question, interpreted and analyzed by you in a synthesized way.

• Make sure your research question is not too broad or too narrow.  Is it manageable?
• Begin writing down terms that are related to your question. These will be useful for searches later.
• If you have the opportunity, discuss your topic with your professor and your class mates.

2. Decide on the scope of your review

How many studies do you need to look at? How comprehensive should it be? How many years should it cover? 

• This may depend on your assignment.  How many sources does the assignment require?

3. Select the databases you will use to conduct your searches.

Make a list of the databases you will search. 

Where to find databases:

• use the tabs on this guide
• Find other databases in the Nursing Information Resources web page
• More on the Medical Library web page
• ... and more on the Yale University Library web page

4. Conduct your searches to find the evidence. Keep track of your searches.

• Use the key words in your question, as well as synonyms for those words, as terms in your search. Use the database tutorials for help.
• Save the searches in the databases. This saves time when you want to redo, or modify, the searches. It is also helpful to use as a guide is the searches are not finding any useful results.
• Review the abstracts of research studies carefully. This will save you time.
• Use the bibliographies and references of research studies you find to locate others.
• Check with your professor, or a subject expert in the field, if you are missing any key works in the field.
• Ask your librarian for help at any time.
• Use a citation manager, such as EndNote as the repository for your citations. See the EndNote tutorials for help.

Review the literature

Some questions to help you analyze the research:

• What was the research question of the study you are reviewing? What were the authors trying to discover?
• Was the research funded by a source that could influence the findings?
• What were the research methodologies? Analyze its literature review, the samples and variables used, the results, and the conclusions.
• Does the research seem to be complete? Could it have been conducted more soundly? What further questions does it raise?
• If there are conflicting studies, why do you think that is?
• How are the authors viewed in the field? Has this study been cited? If so, how has it been analyzed?

Tips: 

• Review the abstracts carefully.  
• Keep careful notes so that you may track your thought processes during the research process.
• Create a matrix of the studies for easy analysis, and synthesis, across all of the studies.
• << Previous: Recommended Books
• Last Updated: Jun 20, 2024 9:08 AM
• URL: https://guides.library.yale.edu/YSNDoctoral

• USC Libraries
• Research Guides

Organizing Your Social Sciences Research Paper

• 5. The Literature Review
• Purpose of Guide
• Design Flaws to Avoid
• Independent and Dependent Variables
• Glossary of Research Terms
• Reading Research Effectively
• Narrowing a Topic Idea
• Broadening a Topic Idea
• Extending the Timeliness of a Topic Idea
• Academic Writing Style
• Applying Critical Thinking
• Choosing a Title
• Making an Outline
• Paragraph Development
• Research Process Video Series
• Executive Summary
• The C.A.R.S. Model
• Background Information
• The Research Problem/Question
• Theoretical Framework
• Citation Tracking
• Content Alert Services
• Evaluating Sources
• Primary Sources
• Secondary Sources
• Tiertiary Sources
• Scholarly vs. Popular Publications
• Qualitative Methods
• Quantitative Methods
• Insiderness
• Using Non-Textual Elements
• Limitations of the Study
• Common Grammar Mistakes
• Writing Concisely
• Avoiding Plagiarism
• Footnotes or Endnotes?
• Further Readings
• Generative AI and Writing
• USC Libraries Tutorials and Other Guides
• Bibliography

A literature review surveys prior research published in books, scholarly articles, and any other sources relevant to a particular issue, area of research, or theory, and by so doing, provides a description, summary, and critical evaluation of these works in relation to the research problem being investigated. Literature reviews are designed to provide an overview of sources you have used in researching a particular topic and to demonstrate to your readers how your research fits within existing scholarship about the topic.

Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . Fourth edition. Thousand Oaks, CA: SAGE, 2014.

Importance of a Good Literature Review

A literature review may consist of simply a summary of key sources, but in the social sciences, a literature review usually has an organizational pattern and combines both summary and synthesis, often within specific conceptual categories . A summary is a recap of the important information of the source, but a synthesis is a re-organization, or a reshuffling, of that information in a way that informs how you are planning to investigate a research problem. The analytical features of a literature review might:

• Give a new interpretation of old material or combine new with old interpretations,
• Trace the intellectual progression of the field, including major debates,
• Depending on the situation, evaluate the sources and advise the reader on the most pertinent or relevant research, or
• Usually in the conclusion of a literature review, identify where gaps exist in how a problem has been researched to date.

Given this, the purpose of a literature review is to:

• Place each work in the context of its contribution to understanding the research problem being studied.
• Describe the relationship of each work to the others under consideration.
• Identify new ways to interpret prior research.
• Reveal any gaps that exist in the literature.
• Resolve conflicts amongst seemingly contradictory previous studies.
• Identify areas of prior scholarship to prevent duplication of effort.
• Point the way in fulfilling a need for additional research.
• Locate your own research within the context of existing literature [very important].

Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper. 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Jesson, Jill. Doing Your Literature Review: Traditional and Systematic Techniques . Los Angeles, CA: SAGE, 2011; Knopf, Jeffrey W. "Doing a Literature Review." PS: Political Science and Politics 39 (January 2006): 127-132; Ridley, Diana. The Literature Review: A Step-by-Step Guide for Students . 2nd ed. Los Angeles, CA: SAGE, 2012.

Types of Literature Reviews

It is important to think of knowledge in a given field as consisting of three layers. First, there are the primary studies that researchers conduct and publish. Second are the reviews of those studies that summarize and offer new interpretations built from and often extending beyond the primary studies. Third, there are the perceptions, conclusions, opinion, and interpretations that are shared informally among scholars that become part of the body of epistemological traditions within the field.

In composing a literature review, it is important to note that it is often this third layer of knowledge that is cited as "true" even though it often has only a loose relationship to the primary studies and secondary literature reviews. Given this, while literature reviews are designed to provide an overview and synthesis of pertinent sources you have explored, there are a number of approaches you could adopt depending upon the type of analysis underpinning your study.

Argumentative Review This form examines literature selectively in order to support or refute an argument, deeply embedded assumption, or philosophical problem already established in the literature. The purpose is to develop a body of literature that establishes a contrarian viewpoint. Given the value-laden nature of some social science research [e.g., educational reform; immigration control], argumentative approaches to analyzing the literature can be a legitimate and important form of discourse. However, note that they can also introduce problems of bias when they are used to make summary claims of the sort found in systematic reviews [see below].

Integrative Review Considered a form of research that reviews, critiques, and synthesizes representative literature on a topic in an integrated way such that new frameworks and perspectives on the topic are generated. The body of literature includes all studies that address related or identical hypotheses or research problems. A well-done integrative review meets the same standards as primary research in regard to clarity, rigor, and replication. This is the most common form of review in the social sciences.

Historical Review Few things rest in isolation from historical precedent. Historical literature reviews focus on examining research throughout a period of time, often starting with the first time an issue, concept, theory, phenomena emerged in the literature, then tracing its evolution within the scholarship of a discipline. The purpose is to place research in a historical context to show familiarity with state-of-the-art developments and to identify the likely directions for future research.

Methodological Review A review does not always focus on what someone said [findings], but how they came about saying what they say [method of analysis]. Reviewing methods of analysis provides a framework of understanding at different levels [i.e. those of theory, substantive fields, research approaches, and data collection and analysis techniques], how researchers draw upon a wide variety of knowledge ranging from the conceptual level to practical documents for use in fieldwork in the areas of ontological and epistemological consideration, quantitative and qualitative integration, sampling, interviewing, data collection, and data analysis. This approach helps highlight ethical issues which you should be aware of and consider as you go through your own study.

Systematic Review This form consists of an overview of existing evidence pertinent to a clearly formulated research question, which uses pre-specified and standardized methods to identify and critically appraise relevant research, and to collect, report, and analyze data from the studies that are included in the review. The goal is to deliberately document, critically evaluate, and summarize scientifically all of the research about a clearly defined research problem . Typically it focuses on a very specific empirical question, often posed in a cause-and-effect form, such as "To what extent does A contribute to B?" This type of literature review is primarily applied to examining prior research studies in clinical medicine and allied health fields, but it is increasingly being used in the social sciences.

Theoretical Review The purpose of this form is to examine the corpus of theory that has accumulated in regard to an issue, concept, theory, phenomena. The theoretical literature review helps to establish what theories already exist, the relationships between them, to what degree the existing theories have been investigated, and to develop new hypotheses to be tested. Often this form is used to help establish a lack of appropriate theories or reveal that current theories are inadequate for explaining new or emerging research problems. The unit of analysis can focus on a theoretical concept or a whole theory or framework.

NOTE: Most often the literature review will incorporate some combination of types. For example, a review that examines literature supporting or refuting an argument, assumption, or philosophical problem related to the research problem will also need to include writing supported by sources that establish the history of these arguments in the literature.

Baumeister, Roy F. and Mark R. Leary. "Writing Narrative Literature Reviews."  Review of General Psychology 1 (September 1997): 311-320; Mark R. Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Kennedy, Mary M. "Defining a Literature." Educational Researcher 36 (April 2007): 139-147; Petticrew, Mark and Helen Roberts. Systematic Reviews in the Social Sciences: A Practical Guide . Malden, MA: Blackwell Publishers, 2006; Torracro, Richard. "Writing Integrative Literature Reviews: Guidelines and Examples." Human Resource Development Review 4 (September 2005): 356-367; Rocco, Tonette S. and Maria S. Plakhotnik. "Literature Reviews, Conceptual Frameworks, and Theoretical Frameworks: Terms, Functions, and Distinctions." Human Ressource Development Review 8 (March 2008): 120-130; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016.

Structure and Writing Style

I.  Thinking About Your Literature Review

The structure of a literature review should include the following in support of understanding the research problem :

• An overview of the subject, issue, or theory under consideration, along with the objectives of the literature review,
• Division of works under review into themes or categories [e.g. works that support a particular position, those against, and those offering alternative approaches entirely],
• An explanation of how each work is similar to and how it varies from the others,
• Conclusions as to which pieces are best considered in their argument, are most convincing of their opinions, and make the greatest contribution to the understanding and development of their area of research.

The critical evaluation of each work should consider :

• Provenance -- what are the author's credentials? Are the author's arguments supported by evidence [e.g. primary historical material, case studies, narratives, statistics, recent scientific findings]?
• Methodology -- were the techniques used to identify, gather, and analyze the data appropriate to addressing the research problem? Was the sample size appropriate? Were the results effectively interpreted and reported?
• Objectivity -- is the author's perspective even-handed or prejudicial? Is contrary data considered or is certain pertinent information ignored to prove the author's point?
• Persuasiveness -- which of the author's theses are most convincing or least convincing?
• Validity -- are the author's arguments and conclusions convincing? Does the work ultimately contribute in any significant way to an understanding of the subject?

II.  Development of the Literature Review

Four Basic Stages of Writing 1.  Problem formulation -- which topic or field is being examined and what are its component issues? 2.  Literature search -- finding materials relevant to the subject being explored. 3.  Data evaluation -- determining which literature makes a significant contribution to the understanding of the topic. 4.  Analysis and interpretation -- discussing the findings and conclusions of pertinent literature.

Consider the following issues before writing the literature review: Clarify If your assignment is not specific about what form your literature review should take, seek clarification from your professor by asking these questions: 1.  Roughly how many sources would be appropriate to include? 2.  What types of sources should I review (books, journal articles, websites; scholarly versus popular sources)? 3.  Should I summarize, synthesize, or critique sources by discussing a common theme or issue? 4.  Should I evaluate the sources in any way beyond evaluating how they relate to understanding the research problem? 5.  Should I provide subheadings and other background information, such as definitions and/or a history? Find Models Use the exercise of reviewing the literature to examine how authors in your discipline or area of interest have composed their literature review sections. Read them to get a sense of the types of themes you might want to look for in your own research or to identify ways to organize your final review. The bibliography or reference section of sources you've already read, such as required readings in the course syllabus, are also excellent entry points into your own research. Narrow the Topic The narrower your topic, the easier it will be to limit the number of sources you need to read in order to obtain a good survey of relevant resources. Your professor will probably not expect you to read everything that's available about the topic, but you'll make the act of reviewing easier if you first limit scope of the research problem. A good strategy is to begin by searching the USC Libraries Catalog for recent books about the topic and review the table of contents for chapters that focuses on specific issues. You can also review the indexes of books to find references to specific issues that can serve as the focus of your research. For example, a book surveying the history of the Israeli-Palestinian conflict may include a chapter on the role Egypt has played in mediating the conflict, or look in the index for the pages where Egypt is mentioned in the text. Consider Whether Your Sources are Current Some disciplines require that you use information that is as current as possible. This is particularly true in disciplines in medicine and the sciences where research conducted becomes obsolete very quickly as new discoveries are made. However, when writing a review in the social sciences, a survey of the history of the literature may be required. In other words, a complete understanding the research problem requires you to deliberately examine how knowledge and perspectives have changed over time. Sort through other current bibliographies or literature reviews in the field to get a sense of what your discipline expects. You can also use this method to explore what is considered by scholars to be a "hot topic" and what is not.

III.  Ways to Organize Your Literature Review

Chronology of Events If your review follows the chronological method, you could write about the materials according to when they were published. This approach should only be followed if a clear path of research building on previous research can be identified and that these trends follow a clear chronological order of development. For example, a literature review that focuses on continuing research about the emergence of German economic power after the fall of the Soviet Union. By Publication Order your sources by publication chronology, then, only if the order demonstrates a more important trend. For instance, you could order a review of literature on environmental studies of brown fields if the progression revealed, for example, a change in the soil collection practices of the researchers who wrote and/or conducted the studies. Thematic [“conceptual categories”] A thematic literature review is the most common approach to summarizing prior research in the social and behavioral sciences. Thematic reviews are organized around a topic or issue, rather than the progression of time, although the progression of time may still be incorporated into a thematic review. For example, a review of the Internet’s impact on American presidential politics could focus on the development of online political satire. While the study focuses on one topic, the Internet’s impact on American presidential politics, it would still be organized chronologically reflecting technological developments in media. The difference in this example between a "chronological" and a "thematic" approach is what is emphasized the most: themes related to the role of the Internet in presidential politics. Note that more authentic thematic reviews tend to break away from chronological order. A review organized in this manner would shift between time periods within each section according to the point being made. Methodological A methodological approach focuses on the methods utilized by the researcher. For the Internet in American presidential politics project, one methodological approach would be to look at cultural differences between the portrayal of American presidents on American, British, and French websites. Or the review might focus on the fundraising impact of the Internet on a particular political party. A methodological scope will influence either the types of documents in the review or the way in which these documents are discussed.

Other Sections of Your Literature Review Once you've decided on the organizational method for your literature review, the sections you need to include in the paper should be easy to figure out because they arise from your organizational strategy. In other words, a chronological review would have subsections for each vital time period; a thematic review would have subtopics based upon factors that relate to the theme or issue. However, sometimes you may need to add additional sections that are necessary for your study, but do not fit in the organizational strategy of the body. What other sections you include in the body is up to you. However, only include what is necessary for the reader to locate your study within the larger scholarship about the research problem.

Here are examples of other sections, usually in the form of a single paragraph, you may need to include depending on the type of review you write:

• Current Situation : Information necessary to understand the current topic or focus of the literature review.
• Sources Used : Describes the methods and resources [e.g., databases] you used to identify the literature you reviewed.
• History : The chronological progression of the field, the research literature, or an idea that is necessary to understand the literature review, if the body of the literature review is not already a chronology.
• Selection Methods : Criteria you used to select (and perhaps exclude) sources in your literature review. For instance, you might explain that your review includes only peer-reviewed [i.e., scholarly] sources.
• Standards : Description of the way in which you present your information.
• Questions for Further Research : What questions about the field has the review sparked? How will you further your research as a result of the review?

IV.  Writing Your Literature Review

Once you've settled on how to organize your literature review, you're ready to write each section. When writing your review, keep in mind these issues.

Use Evidence A literature review section is, in this sense, just like any other academic research paper. Your interpretation of the available sources must be backed up with evidence [citations] that demonstrates that what you are saying is valid. Be Selective Select only the most important points in each source to highlight in the review. The type of information you choose to mention should relate directly to the research problem, whether it is thematic, methodological, or chronological. Related items that provide additional information, but that are not key to understanding the research problem, can be included in a list of further readings . Use Quotes Sparingly Some short quotes are appropriate if you want to emphasize a point, or if what an author stated cannot be easily paraphrased. Sometimes you may need to quote certain terminology that was coined by the author, is not common knowledge, or taken directly from the study. Do not use extensive quotes as a substitute for using your own words in reviewing the literature. Summarize and Synthesize Remember to summarize and synthesize your sources within each thematic paragraph as well as throughout the review. Recapitulate important features of a research study, but then synthesize it by rephrasing the study's significance and relating it to your own work and the work of others. Keep Your Own Voice While the literature review presents others' ideas, your voice [the writer's] should remain front and center. For example, weave references to other sources into what you are writing but maintain your own voice by starting and ending the paragraph with your own ideas and wording. Use Caution When Paraphrasing When paraphrasing a source that is not your own, be sure to represent the author's information or opinions accurately and in your own words. Even when paraphrasing an author’s work, you still must provide a citation to that work.

V.  Common Mistakes to Avoid

These are the most common mistakes made in reviewing social science research literature.

• Sources in your literature review do not clearly relate to the research problem;
• You do not take sufficient time to define and identify the most relevant sources to use in the literature review related to the research problem;
• Relies exclusively on secondary analytical sources rather than including relevant primary research studies or data;
• Uncritically accepts another researcher's findings and interpretations as valid, rather than examining critically all aspects of the research design and analysis;
• Does not describe the search procedures that were used in identifying the literature to review;
• Reports isolated statistical results rather than synthesizing them in chi-squared or meta-analytic methods; and,
• Only includes research that validates assumptions and does not consider contrary findings and alternative interpretations found in the literature.

Cook, Kathleen E. and Elise Murowchick. “Do Literature Review Skills Transfer from One Course to Another?” Psychology Learning and Teaching 13 (March 2014): 3-11; Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Jesson, Jill. Doing Your Literature Review: Traditional and Systematic Techniques . London: SAGE, 2011; Literature Review Handout. Online Writing Center. Liberty University; Literature Reviews. The Writing Center. University of North Carolina; Onwuegbuzie, Anthony J. and Rebecca Frels. Seven Steps to a Comprehensive Literature Review: A Multimodal and Cultural Approach . Los Angeles, CA: SAGE, 2016; Ridley, Diana. The Literature Review: A Step-by-Step Guide for Students . 2nd ed. Los Angeles, CA: SAGE, 2012; Randolph, Justus J. “A Guide to Writing the Dissertation Literature Review." Practical Assessment, Research, and Evaluation. vol. 14, June 2009; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016; Taylor, Dena. The Literature Review: A Few Tips On Conducting It. University College Writing Centre. University of Toronto; Writing a Literature Review. Academic Skills Centre. University of Canberra.

Writing Tip

Break Out of Your Disciplinary Box!

Thinking interdisciplinarily about a research problem can be a rewarding exercise in applying new ideas, theories, or concepts to an old problem. For example, what might cultural anthropologists say about the continuing conflict in the Middle East? In what ways might geographers view the need for better distribution of social service agencies in large cities than how social workers might study the issue? You don’t want to substitute a thorough review of core research literature in your discipline for studies conducted in other fields of study. However, particularly in the social sciences, thinking about research problems from multiple vectors is a key strategy for finding new solutions to a problem or gaining a new perspective. Consult with a librarian about identifying research databases in other disciplines; almost every field of study has at least one comprehensive database devoted to indexing its research literature.

Frodeman, Robert. The Oxford Handbook of Interdisciplinarity . New York: Oxford University Press, 2010.

Another Writing Tip

Don't Just Review for Content!

While conducting a review of the literature, maximize the time you devote to writing this part of your paper by thinking broadly about what you should be looking for and evaluating. Review not just what scholars are saying, but how are they saying it. Some questions to ask:

• How are they organizing their ideas?
• What methods have they used to study the problem?
• What theories have been used to explain, predict, or understand their research problem?
• What sources have they cited to support their conclusions?
• How have they used non-textual elements [e.g., charts, graphs, figures, etc.] to illustrate key points?

When you begin to write your literature review section, you'll be glad you dug deeper into how the research was designed and constructed because it establishes a means for developing more substantial analysis and interpretation of the research problem.

Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1 998.

Yet Another Writing Tip

When Do I Know I Can Stop Looking and Move On?

Here are several strategies you can utilize to assess whether you've thoroughly reviewed the literature:

• Look for repeating patterns in the research findings . If the same thing is being said, just by different people, then this likely demonstrates that the research problem has hit a conceptual dead end. At this point consider: Does your study extend current research?  Does it forge a new path? Or, does is merely add more of the same thing being said?
• Look at sources the authors cite to in their work . If you begin to see the same researchers cited again and again, then this is often an indication that no new ideas have been generated to address the research problem.
• Search Google Scholar to identify who has subsequently cited leading scholars already identified in your literature review [see next sub-tab]. This is called citation tracking and there are a number of sources that can help you identify who has cited whom, particularly scholars from outside of your discipline. Here again, if the same authors are being cited again and again, this may indicate no new literature has been written on the topic.

Onwuegbuzie, Anthony J. and Rebecca Frels. Seven Steps to a Comprehensive Literature Review: A Multimodal and Cultural Approach . Los Angeles, CA: Sage, 2016; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016.

• << Previous: Theoretical Framework
• Next: Citation Tracking >>
• Last Updated: Sep 17, 2024 10:59 AM
• URL: https://libguides.usc.edu/writingguide

• University of Texas Libraries

Literature Reviews

• What is a literature review?
• Steps in the Literature Review Process
• Define your research question
• Determine inclusion and exclusion criteria
• Choose databases and search
• Review Results
• Synthesize Results
• Analyze Results
• Librarian Support
• Artificial Intelligence (AI) Tools

What is a Literature Review?

A literature or narrative review is a comprehensive review and analysis of the published literature on a specific topic or research question. The literature that is reviewed contains: books, articles, academic articles, conference proceedings, association papers, and dissertations. It contains the most pertinent studies and points to important past and current research and practices. It provides background and context, and shows how your research will contribute to the field. 

A literature review should: 

• Provide a comprehensive and updated review of the literature;
• Explain why this review has taken place;
• Articulate a position or hypothesis;
• Acknowledge and account for conflicting and corroborating points of view

From  S age Research Methods

Purpose of a Literature Review

A literature review can be written as an introduction to a study to:

• Demonstrate how a study fills a gap in research
• Compare a study with other research that's been done

Or it can be a separate work (a research article on its own) which:

• Organizes or describes a topic
• Describes variables within a particular issue/problem

Limitations of a Literature Review

Some of the limitations of a literature review are:

• It's a snapshot in time. Unlike other reviews, this one has beginning, a middle and an end. There may be future developments that could make your work less relevant.
• It may be too focused. Some niche studies may miss the bigger picture.
• It can be difficult to be comprehensive. There is no way to make sure all the literature on a topic was considered.
• It is easy to be biased if you stick to top tier journals. There may be other places where people are publishing exemplary research. Look to open access publications and conferences to reflect a more inclusive collection. Also, make sure to include opposing views (and not just supporting evidence).

Source: Grant, Maria J., and Andrew Booth. “A Typology of Reviews: An Analysis of 14 Review Types and Associated Methodologies.” Health Information & Libraries Journal, vol. 26, no. 2, June 2009, pp. 91–108. Wiley Online Library, doi:10.1111/j.1471-1842.2009.00848.x.

Librarian Assistance

For help, please contact the librarian for your subject area.  We have a guide to library specialists by subject .

• Last Updated: Aug 26, 2024 5:59 AM
• URL: https://guides.lib.utexas.edu/literaturereviews

University Libraries

Literature review.

• What is a Literature Review?
• What is Its Purpose?
• 1. Select a Topic
• 2. Set the Topic in Context
• 3. Types of Information Sources
• 4. Use Information Sources
• 5. Get the Information
• 6. Organize / Manage the Information
• 7. Position the Literature Review
• 8. Write the Literature Review

A literature review is a comprehensive summary of previous research on a topic. The literature review surveys scholarly articles, books, and other sources relevant to a particular area of research.  The review should enumerate, describe, summarize, objectively evaluate and clarify this previous research.  It should give a theoretical base for the research and help you (the author) determine the nature of your research.  The literature review acknowledges the work of previous researchers, and in so doing, assures the reader that your work has been well conceived.  It is assumed that by mentioning a previous work in the field of study, that the author has read, evaluated, and assimiliated that work into the work at hand.

A literature review creates a "landscape" for the reader, giving her or him a full understanding of the developments in the field.  This landscape informs the reader that the author has indeed assimilated all (or the vast majority of) previous, significant works in the field into her or his research. 

 "In writing the literature review, the purpose is to convey to the reader what knowledge and ideas have been established on a topic, and what their strengths and weaknesses are. The literature review must be defined by a guiding concept (eg. your research objective, the problem or issue you are discussing, or your argumentative thesis). It is not just a descriptive list of the material available, or a set of summaries.( http://www.writing.utoronto.ca/advice/specific-types-of-writing/literature-review )

Recommended Reading

• Next: What is Its Purpose? >>
• Last Updated: Oct 2, 2023 12:34 PM

Literature Review: Purpose of a Literature Review

• Literature Review
• Purpose of a Literature Review
• Work in Progress
• Compiling & Writing
• Books, Articles, & Web Pages
• Types of Literature Reviews
• Departmental Differences
• Citation Styles & Plagiarism
• Know the Difference! Systematic Review vs. Literature Review

The purpose of a literature review is to:

• Provide a foundation of knowledge on a topic
• Identify areas of prior scholarship to prevent duplication and give credit to other researchers
• Identify inconstancies: gaps in research, conflicts in previous studies, open questions left from other research
• Identify the need for additional research (justifying your research)
• Identify the relationship of works in the context of their contribution to the topic and other works
• Place your own research within the context of existing literature, making a case for why further study is needed.

Videos & Tutorials

VIDEO: What is the role of a literature review in research? What's it mean to "review" the literature? Get the big picture of what to expect as part of the process. This video is published under a Creative Commons 3.0 BY-NC-SA US license. License, credits, and contact information can be found here: https://www.lib.ncsu.edu/tutorials/litreview/

Elements in a Literature Review

• Elements in a Literature Review txt of infographic
• << Previous: Literature Review
• Next: Searching >>
• Last Updated: Sep 10, 2024 11:32 AM
• URL: https://uscupstate.libguides.com/Literature_Review

How To Structure Your Literature Review

3 options to help structure your chapter.

By: Amy Rommelspacher (PhD) | Reviewer: Dr Eunice Rautenbach | November 2020 (Updated May 2023)

Writing the literature review chapter can seem pretty daunting when you’re piecing together your dissertation or thesis. As  we’ve discussed before , a good literature review needs to achieve a few very important objectives – it should:

• Demonstrate your knowledge of the research topic
• Identify the gaps in the literature and show how your research links to these
• Provide the foundation for your conceptual framework (if you have one)
• Inform your own  methodology and research design

To achieve this, your literature review needs a well-thought-out structure . Get the structure of your literature review chapter wrong and you’ll struggle to achieve these objectives. Don’t worry though – in this post, we’ll look at how to structure your literature review for maximum impact (and marks!).

But wait – is this the right time?

Deciding on the structure of your literature review should come towards the end of the literature review process – after you have collected and digested the literature, but before you start writing the chapter. 

In other words, you need to first develop a rich understanding of the literature before you even attempt to map out a structure. There’s no use trying to develop a structure before you’ve fully wrapped your head around the existing research.

Equally importantly, you need to have a structure in place before you start writing , or your literature review will most likely end up a rambling, disjointed mess. 

Importantly, don’t feel that once you’ve defined a structure you can’t iterate on it. It’s perfectly natural to adjust as you engage in the writing process. As we’ve discussed before , writing is a way of developing your thinking, so it’s quite common for your thinking to change – and therefore, for your chapter structure to change – as you write. 

Need a helping hand?

Like any other chapter in your thesis or dissertation, your literature review needs to have a clear, logical structure. At a minimum, it should have three essential components – an  introduction , a  body   and a  conclusion . 

Let’s take a closer look at each of these.

1: The Introduction Section

Just like any good introduction, the introduction section of your literature review should introduce the purpose and layout (organisation) of the chapter. In other words, your introduction needs to give the reader a taste of what’s to come, and how you’re going to lay that out. Essentially, you should provide the reader with a high-level roadmap of your chapter to give them a taste of the journey that lies ahead.

Here’s an example of the layout visualised in a literature review introduction:

Your introduction should also outline your topic (including any tricky terminology or jargon) and provide an explanation of the scope of your literature review – in other words, what you  will   and  won’t   be covering (the delimitations ). This helps ringfence your review and achieve a clear focus . The clearer and narrower your focus, the deeper you can dive into the topic (which is typically where the magic lies). 

Depending on the nature of your project, you could also present your stance or point of view at this stage. In other words, after grappling with the literature you’ll have an opinion about what the trends and concerns are in the field as well as what’s lacking. The introduction section can then present these ideas so that it is clear to examiners that you’re aware of how your research connects with existing knowledge .

2: The Body Section

The body of your literature review is the centre of your work. This is where you’ll present, analyse, evaluate and synthesise the existing research. In other words, this is where you’re going to earn (or lose) the most marks. Therefore, it’s important to carefully think about how you will organise your discussion to present it in a clear way. 

The body of your literature review should do just as the description of this chapter suggests. It should “review” the literature – in other words, identify, analyse, and synthesise it. So, when thinking about structuring your literature review, you need to think about which structural approach will provide the best “review” for your specific type of research and objectives (we’ll get to this shortly).

There are (broadly speaking)  three options  for organising your literature review.

Option 1: Chronological (according to date)

Organising the literature chronologically is one of the simplest ways to structure your literature review. You start with what was published first and work your way through the literature until you reach the work published most recently. Pretty straightforward.

The benefit of this option is that it makes it easy to discuss the developments and debates in the field as they emerged over time. Organising your literature chronologically also allows you to highlight how specific articles or pieces of work might have changed the course of the field – in other words, which research has had the most impact . Therefore, this approach is very useful when your research is aimed at understanding how the topic has unfolded over time and is often used by scholars in the field of history. That said, this approach can be utilised by anyone that wants to explore change over time .

For example , if a student of politics is investigating how the understanding of democracy has evolved over time, they could use the chronological approach to provide a narrative that demonstrates how this understanding has changed through the ages.

Here are some questions you can ask yourself to help you structure your literature review chronologically.

• What is the earliest literature published relating to this topic?
• How has the field changed over time? Why?
• What are the most recent discoveries/theories?

In some ways, chronology plays a part whichever way you decide to structure your literature review, because you will always, to a certain extent, be analysing how the literature has developed. However, with the chronological approach, the emphasis is very firmly on how the discussion has evolved over time , as opposed to how all the literature links together (which we’ll discuss next ).

Option 2: Thematic (grouped by theme)

The thematic approach to structuring a literature review means organising your literature by theme or category – for example, by independent variables (i.e. factors that have an impact on a specific outcome).

As you’ve been collecting and synthesising literature , you’ll likely have started seeing some themes or patterns emerging. You can then use these themes or patterns as a structure for your body discussion. The thematic approach is the most common approach and is useful for structuring literature reviews in most fields.

For example, if you were researching which factors contributed towards people trusting an organisation, you might find themes such as consumers’ perceptions of an organisation’s competence, benevolence and integrity. Structuring your literature review thematically would mean structuring your literature review’s body section to discuss each of these themes, one section at a time.

Here are some questions to ask yourself when structuring your literature review by themes:

• Are there any patterns that have come to light in the literature?
• What are the central themes and categories used by the researchers?
• Do I have enough evidence of these themes?

PS – you can see an example of a thematically structured literature review in our literature review sample walkthrough video here.

Option 3: Methodological

The methodological option is a way of structuring your literature review by the research methodologies used . In other words, organising your discussion based on the angle from which each piece of research was approached – for example, qualitative , quantitative or mixed  methodologies.

Structuring your literature review by methodology can be useful if you are drawing research from a variety of disciplines and are critiquing different methodologies. The point of this approach is to question  how  existing research has been conducted, as opposed to  what  the conclusions and/or findings the research were.

For example, a sociologist might centre their research around critiquing specific fieldwork practices. Their literature review will then be a summary of the fieldwork methodologies used by different studies.

Here are some questions you can ask yourself when structuring your literature review according to methodology:

• Which methodologies have been utilised in this field?
• Which methodology is the most popular (and why)?
• What are the strengths and weaknesses of the various methodologies?
• How can the existing methodologies inform my own methodology?

3: The Conclusion Section

Once you’ve completed the body section of your literature review using one of the structural approaches we discussed above, you’ll need to “wrap up” your literature review and pull all the pieces together to set the direction for the rest of your dissertation or thesis.

The conclusion is where you’ll present the key findings of your literature review. In this section, you should emphasise the research that is especially important to your research questions and highlight the gaps that exist in the literature. Based on this, you need to make it clear what you will add to the literature – in other words, justify your own research by showing how it will help fill one or more of the gaps you just identified.

Last but not least, if it’s your intention to develop a conceptual framework for your dissertation or thesis, the conclusion section is a good place to present this.

Example: Thematically Structured Review

In the video below, we unpack a literature review chapter so that you can see an example of a thematically structure review in practice.

Let’s Recap

In this article, we’ve  discussed how to structure your literature review for maximum impact. Here’s a quick recap of what  you need to keep in mind when deciding on your literature review structure:

• Just like other chapters, your literature review needs a clear introduction , body and conclusion .
• The introduction section should provide an overview of what you will discuss in your literature review.
• The body section of your literature review can be organised by chronology , theme or methodology . The right structural approach depends on what you’re trying to achieve with your research.
• The conclusion section should draw together the key findings of your literature review and link them to your research questions.

If you’re ready to get started, be sure to download our free literature review template to fast-track your chapter outline.

Psst… there’s more!

This post is an extract from our bestselling short course, Literature Review Bootcamp . If you want to work smart, you don't want to miss this .

29 Comments

Great work. This is exactly what I was looking for and helps a lot together with your previous post on literature review. One last thing is missing: a link to a great literature chapter of an journal article (maybe with comments of the different sections in this review chapter). Do you know any great literature review chapters?

I agree with you Marin… A great piece

I agree with Marin. This would be quite helpful if you annotate a nicely structured literature from previously published research articles.

Awesome article for my research.

I thank you immensely for this wonderful guide

It is indeed thought and supportive work for the futurist researcher and students

Very educative and good time to get guide. Thank you

Great work, very insightful. Thank you.

Thanks for this wonderful presentation. My question is that do I put all the variables into a single conceptual framework or each hypothesis will have it own conceptual framework?

Thank you very much, very helpful

This is very educative and precise . Thank you very much for dropping this kind of write up .

Pheeww, so damn helpful, thank you for this informative piece.

I’m doing a research project topic ; stool analysis for parasitic worm (enteric) worm, how do I structure it, thanks.

comprehensive explanation. Help us by pasting the URL of some good “literature review” for better understanding.

great piece. thanks for the awesome explanation. it is really worth sharing. I have a little question, if anyone can help me out, which of the options in the body of literature can be best fit if you are writing an architectural thesis that deals with design?

I am doing a research on nanofluids how can l structure it?

Beautifully clear.nThank you!

Lucid! Thankyou!

Brilliant work, well understood, many thanks

I like how this was so clear with simple language 😊😊 thank you so much 😊 for these information 😊

Insightful. I was struggling to come up with a sensible literature review but this has been really helpful. Thank you!

You have given thought-provoking information about the review of the literature.

Thank you. It has made my own research better and to impart your work to students I teach

I learnt a lot from this teaching. It’s a great piece.

I am doing research on EFL teacher motivation for his/her job. How Can I structure it? Is there any detailed template, additional to this?

You are so cool! I do not think I’ve read through something like this before. So nice to find somebody with some genuine thoughts on this issue. Seriously.. thank you for starting this up. This site is one thing that is required on the internet, someone with a little originality!

I’m asked to do conceptual, theoretical and empirical literature, and i just don’t know how to structure it

Asking questions are actually fastidious thing if you are not understanding anything fully, but this article presents good understanding yet.

thank you SOOO much it is really helpful ..

Submit a Comment Cancel reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

• Print Friendly

• Resources Home 🏠
• Try SciSpace Copilot
• Search research papers
• Add Copilot Extension
• Try AI Detector
• Try Paraphraser
• Try Citation Generator
• April Papers
• June Papers
• July Papers

How To Write A Literature Review - A Complete Guide

Table of Contents

A literature review is much more than just another section in your research paper. It forms the very foundation of your research. It is a formal piece of writing where you analyze the existing theoretical framework, principles, and assumptions and use that as a base to shape your approach to the research question.

Curating and drafting a solid literature review section not only lends more credibility to your research paper but also makes your research tighter and better focused. But, writing literature reviews is a difficult task. It requires extensive reading, plus you have to consider market trends and technological and political changes, which tend to change in the blink of an eye.

Now streamline your literature review process with the help of SciSpace Copilot. With this AI research assistant, you can efficiently synthesize and analyze a vast amount of information, identify key themes and trends, and uncover gaps in the existing research. Get real-time explanations, summaries, and answers to your questions for the paper you're reviewing, making navigating and understanding the complex literature landscape easier.

In this comprehensive guide, we will explore everything from the definition of a literature review, its appropriate length, various types of literature reviews, and how to write one.

What is a literature review?

A literature review is a collation of survey, research, critical evaluation, and assessment of the existing literature in a preferred domain.

Eminent researcher and academic Arlene Fink, in her book Conducting Research Literature Reviews , defines it as the following:

“A literature review surveys books, scholarly articles, and any other sources relevant to a particular issue, area of research, or theory, and by so doing, provides a description, summary, and critical evaluation of these works in relation to the research problem being investigated.

Literature reviews are designed to provide an overview of sources you have explored while researching a particular topic, and to demonstrate to your readers how your research fits within a larger field of study.”

Simply put, a literature review can be defined as a critical discussion of relevant pre-existing research around your research question and carving out a definitive place for your study in the existing body of knowledge. Literature reviews can be presented in multiple ways: a section of an article, the whole research paper itself, or a chapter of your thesis.

A literature review does function as a summary of sources, but it also allows you to analyze further, interpret, and examine the stated theories, methods, viewpoints, and, of course, the gaps in the existing content.

As an author, you can discuss and interpret the research question and its various aspects and debate your adopted methods to support the claim.

What is the purpose of a literature review?

A literature review is meant to help your readers understand the relevance of your research question and where it fits within the existing body of knowledge. As a researcher, you should use it to set the context, build your argument, and establish the need for your study.

What is the importance of a literature review?

The literature review is a critical part of research papers because it helps you:

• Gain an in-depth understanding of your research question and the surrounding area
• Convey that you have a thorough understanding of your research area and are up-to-date with the latest changes and advancements
• Establish how your research is connected or builds on the existing body of knowledge and how it could contribute to further research
• Elaborate on the validity and suitability of your theoretical framework and research methodology
• Identify and highlight gaps and shortcomings in the existing body of knowledge and how things need to change
• Convey to readers how your study is different or how it contributes to the research area

How long should a literature review be?

Ideally, the literature review should take up 15%-40% of the total length of your manuscript. So, if you have a 10,000-word research paper, the minimum word count could be 1500.

Your literature review format depends heavily on the kind of manuscript you are writing — an entire chapter in case of doctoral theses, a part of the introductory section in a research article, to a full-fledged review article that examines the previously published research on a topic.

Another determining factor is the type of research you are doing. The literature review section tends to be longer for secondary research projects than primary research projects.

What are the different types of literature reviews?

All literature reviews are not the same. There are a variety of possible approaches that you can take. It all depends on the type of research you are pursuing.

Here are the different types of literature reviews:

Argumentative review

It is called an argumentative review when you carefully present literature that only supports or counters a specific argument or premise to establish a viewpoint.

Integrative review

It is a type of literature review focused on building a comprehensive understanding of a topic by combining available theoretical frameworks and empirical evidence.

Methodological review

This approach delves into the ''how'' and the ''what" of the research question —  you cannot look at the outcome in isolation; you should also review the methodology used.

Systematic review

This form consists of an overview of existing evidence pertinent to a clearly formulated research question, which uses pre-specified and standardized methods to identify and critically appraise relevant research and collect, report, and analyze data from the studies included in the review.

Meta-analysis review

Meta-analysis uses statistical methods to summarize the results of independent studies. By combining information from all relevant studies, meta-analysis can provide more precise estimates of the effects than those derived from the individual studies included within a review.

Historical review

Historical literature reviews focus on examining research throughout a period, often starting with the first time an issue, concept, theory, or phenomenon emerged in the literature, then tracing its evolution within the scholarship of a discipline. The purpose is to place research in a historical context to show familiarity with state-of-the-art developments and identify future research's likely directions.

Theoretical Review

This form aims to examine the corpus of theory accumulated regarding an issue, concept, theory, and phenomenon. The theoretical literature review helps to establish what theories exist, the relationships between them, the degree the existing approaches have been investigated, and to develop new hypotheses to be tested.

Scoping Review

The Scoping Review is often used at the beginning of an article, dissertation, or research proposal. It is conducted before the research to highlight gaps in the existing body of knowledge and explains why the project should be greenlit.

State-of-the-Art Review

The State-of-the-Art review is conducted periodically, focusing on the most recent research. It describes what is currently known, understood, or agreed upon regarding the research topic and highlights where there are still disagreements.

Can you use the first person in a literature review?

When writing literature reviews, you should avoid the usage of first-person pronouns. It means that instead of "I argue that" or "we argue that," the appropriate expression would be "this research paper argues that."

Do you need an abstract for a literature review?

Ideally, yes. It is always good to have a condensed summary that is self-contained and independent of the rest of your review. As for how to draft one, you can follow the same fundamental idea when preparing an abstract for a literature review. It should also include:

• The research topic and your motivation behind selecting it
• A one-sentence thesis statement
• An explanation of the kinds of literature featured in the review
• Summary of what you've learned
• Conclusions you drew from the literature you reviewed
• Potential implications and future scope for research

Here's an example of the abstract of a literature review

Is a literature review written in the past tense?

Yes, the literature review should ideally be written in the past tense. You should not use the present or future tense when writing one. The exceptions are when you have statements describing events that happened earlier than the literature you are reviewing or events that are currently occurring; then, you can use the past perfect or present perfect tenses.

How many sources for a literature review?

There are multiple approaches to deciding how many sources to include in a literature review section. The first approach would be to look level you are at as a researcher. For instance, a doctoral thesis might need 60+ sources. In contrast, you might only need to refer to 5-15 sources at the undergraduate level.

The second approach is based on the kind of literature review you are doing — whether it is merely a chapter of your paper or if it is a self-contained paper in itself. When it is just a chapter, sources should equal the total number of pages in your article's body. In the second scenario, you need at least three times as many sources as there are pages in your work.

Quick tips on how to write a literature review

To know how to write a literature review, you must clearly understand its impact and role in establishing your work as substantive research material.

You need to follow the below-mentioned steps, to write a literature review:

• Outline the purpose behind the literature review
• Search relevant literature
• Examine and assess the relevant resources
• Discover connections by drawing deep insights from the resources
• Structure planning to write a good literature review

1. Outline and identify the purpose of  a literature review

As a first step on how to write a literature review, you must know what the research question or topic is and what shape you want your literature review to take. Ensure you understand the research topic inside out, or else seek clarifications. You must be able to the answer below questions before you start:

• How many sources do I need to include?
• What kind of sources should I analyze?
• How much should I critically evaluate each source?
• Should I summarize, synthesize or offer a critique of the sources?
• Do I need to include any background information or definitions?

Additionally, you should know that the narrower your research topic is, the swifter it will be for you to restrict the number of sources to be analyzed.

2. Search relevant literature

Dig deeper into search engines to discover what has already been published around your chosen topic. Make sure you thoroughly go through appropriate reference sources like books, reports, journal articles, government docs, and web-based resources.

You must prepare a list of keywords and their different variations. You can start your search from any library’s catalog, provided you are an active member of that institution. The exact keywords can be extended to widen your research over other databases and academic search engines like:

• Google Scholar
• Microsoft Academic
• Science.gov

Besides, it is not advisable to go through every resource word by word. Alternatively, what you can do is you can start by reading the abstract and then decide whether that source is relevant to your research or not.

Additionally, you must spend surplus time assessing the quality and relevance of resources. It would help if you tried preparing a list of citations to ensure that there lies no repetition of authors, publications, or articles in the literature review.

3. Examine and assess the sources

It is nearly impossible for you to go through every detail in the research article. So rather than trying to fetch every detail, you have to analyze and decide which research sources resemble closest and appear relevant to your chosen domain.

While analyzing the sources, you should look to find out answers to questions like:

• What question or problem has the author been describing and debating?
• What is the definition of critical aspects?
• How well the theories, approach, and methodology have been explained?
• Whether the research theory used some conventional or new innovative approach?
• How relevant are the key findings of the work?
• In what ways does it relate to other sources on the same topic?
• What challenges does this research paper pose to the existing theory
• What are the possible contributions or benefits it adds to the subject domain?

Be always mindful that you refer only to credible and authentic resources. It would be best if you always take references from different publications to validate your theory.

Always keep track of important information or data you can present in your literature review right from the beginning. It will help steer your path from any threats of plagiarism and also make it easier to curate an annotated bibliography or reference section.

4. Discover connections

At this stage, you must start deciding on the argument and structure of your literature review. To accomplish this, you must discover and identify the relations and connections between various resources while drafting your abstract.

A few aspects that you should be aware of while writing a literature review include:

• Rise to prominence: Theories and methods that have gained reputation and supporters over time.
• Constant scrutiny: Concepts or theories that repeatedly went under examination.
• Contradictions and conflicts: Theories, both the supporting and the contradictory ones, for the research topic.
• Knowledge gaps: What exactly does it fail to address, and how to bridge them with further research?
• Influential resources: Significant research projects available that have been upheld as milestones or perhaps, something that can modify the current trends

Once you join the dots between various past research works, it will be easier for you to draw a conclusion and identify your contribution to the existing knowledge base.

5. Structure planning to write a good literature review

There exist different ways towards planning and executing the structure of a literature review. The format of a literature review varies and depends upon the length of the research.

Like any other research paper, the literature review format must contain three sections: introduction, body, and conclusion. The goals and objectives of the research question determine what goes inside these three sections.

Nevertheless, a good literature review can be structured according to the chronological, thematic, methodological, or theoretical framework approach.

Literature review samples

1. Standalone

2. As a section of a research paper

How SciSpace Discover makes literature review a breeze?

SciSpace Discover is a one-stop solution to do an effective literature search and get barrier-free access to scientific knowledge. It is an excellent repository where you can find millions of only peer-reviewed articles and full-text PDF files. Here’s more on how you can use it:

Find the right information

Find what you want quickly and easily with comprehensive search filters that let you narrow down papers according to PDF availability, year of publishing, document type, and affiliated institution. Moreover, you can sort the results based on the publishing date, citation count, and relevance.

Assess credibility of papers quickly

When doing the literature review, it is critical to establish the quality of your sources. They form the foundation of your research. SciSpace Discover helps you assess the quality of a source by providing an overview of its references, citations, and performance metrics.

Get the complete picture in no time

SciSpace Discover’s personalized suggestion engine helps you stay on course and get the complete picture of the topic from one place. Every time you visit an article page, it provides you links to related papers. Besides that, it helps you understand what’s trending, who are the top authors, and who are the leading publishers on a topic.

Make referring sources super easy

To ensure you don't lose track of your sources, you must start noting down your references when doing the literature review. SciSpace Discover makes this step effortless. Click the 'cite' button on an article page, and you will receive preloaded citation text in multiple styles — all you've to do is copy-paste it into your manuscript.

Final tips on how to write a literature review

A massive chunk of time and effort is required to write a good literature review. But, if you go about it systematically, you'll be able to save a ton of time and build a solid foundation for your research.

We hope this guide has helped you answer several key questions you have about writing literature reviews.

Would you like to explore SciSpace Discover and kick off your literature search right away? You can get started here .

Frequently Asked Questions (FAQs)

1. how to start a literature review.

• What questions do you want to answer?

• What sources do you need to answer these questions?

• What information do these sources contain?

• How can you use this information to answer your questions?

2. What to include in a literature review?

• A brief background of the problem or issue

• What has previously been done to address the problem or issue

• A description of what you will do in your project

• How this study will contribute to research on the subject

3. Why literature review is important?

The literature review is an important part of any research project because it allows the writer to look at previous studies on a topic and determine existing gaps in the literature, as well as what has already been done. It will also help them to choose the most appropriate method for their own study.

4. How to cite a literature review in APA format?

To cite a literature review in APA style, you need to provide the author's name, the title of the article, and the year of publication. For example: Patel, A. B., & Stokes, G. S. (2012). The relationship between personality and intelligence: A meta-analysis of longitudinal research. Personality and Individual Differences, 53(1), 16-21

5. What are the components of a literature review?

• A brief introduction to the topic, including its background and context. The introduction should also include a rationale for why the study is being conducted and what it will accomplish.

• A description of the methodologies used in the study. This can include information about data collection methods, sample size, and statistical analyses.

• A presentation of the findings in an organized format that helps readers follow along with the author's conclusions.

6. What are common errors in writing literature review?

• Not spending enough time to critically evaluate the relevance of resources, observations and conclusions.

• Totally relying on secondary data while ignoring primary data.

• Letting your personal bias seep into your interpretation of existing literature.

• No detailed explanation of the procedure to discover and identify an appropriate literature review.

7. What are the 5 C's of writing literature review?

• Cite - the sources you utilized and referenced in your research.

• Compare - existing arguments, hypotheses, methodologies, and conclusions found in the knowledge base.

• Contrast - the arguments, topics, methodologies, approaches, and disputes that may be found in the literature.

• Critique - the literature and describe the ideas and opinions you find more convincing and why.

• Connect - the various studies you reviewed in your research.

8. How many sources should a literature review have?

When it is just a chapter, sources should equal the total number of pages in your article's body. if it is a self-contained paper in itself, you need at least three times as many sources as there are pages in your work.

9. Can literature review have diagrams?

• To represent an abstract idea or concept

• To explain the steps of a process or procedure

• To help readers understand the relationships between different concepts

10. How old should sources be in a literature review?

Sources for a literature review should be as current as possible or not older than ten years. The only exception to this rule is if you are reviewing a historical topic and need to use older sources.

11. What are the types of literature review?

• Argumentative review

• Integrative review

• Methodological review

• Systematic review

• Meta-analysis review

• Historical review

• Theoretical review

• Scoping review

• State-of-the-Art review

12. Is a literature review mandatory?

Yes. Literature review is a mandatory part of any research project. It is a critical step in the process that allows you to establish the scope of your research, and provide a background for the rest of your work.

But before you go,

• Six Online Tools for Easy Literature Review
• Evaluating literature review: systematic vs. scoping reviews
• Systematic Approaches to a Successful Literature Review
• Writing Integrative Literature Reviews: Guidelines and Examples

You might also like

Consensus GPT vs. SciSpace GPT: Choose the Best GPT for Research

Literature Review and Theoretical Framework: Understanding the Differences

Types of Essays in Academic Writing - Quick Guide (2024)

Frequently asked questions

What is the purpose of a literature review.

There are several reasons to conduct a literature review at the beginning of a research project:

• To familiarize yourself with the current state of knowledge on your topic
• To ensure that you’re not just repeating what others have already done
• To identify gaps in knowledge and unresolved problems that your research can address
• To develop your theoretical framework and methodology
• To provide an overview of the key findings and debates on the topic

Writing the literature review shows your reader how your work relates to existing research and what new insights it will contribute.

Frequently asked questions: Academic writing

A rhetorical tautology is the repetition of an idea of concept using different words.

Rhetorical tautologies occur when additional words are used to convey a meaning that has already been expressed or implied. For example, the phrase “armed gunman” is a tautology because a “gunman” is by definition “armed.”

A logical tautology is a statement that is always true because it includes all logical possibilities.

Logical tautologies often take the form of “either/or” statements (e.g., “It will rain, or it will not rain”) or employ circular reasoning (e.g., “she is untrustworthy because she can’t be trusted”).

You may have seen both “appendices” or “appendixes” as pluralizations of “ appendix .” Either spelling can be used, but “appendices” is more common (including in APA Style ). Consistency is key here: make sure you use the same spelling throughout your paper.

The purpose of a lab report is to demonstrate your understanding of the scientific method with a hands-on lab experiment. Course instructors will often provide you with an experimental design and procedure. Your task is to write up how you actually performed the experiment and evaluate the outcome.

In contrast, a research paper requires you to independently develop an original argument. It involves more in-depth research and interpretation of sources and data.

A lab report is usually shorter than a research paper.

The sections of a lab report can vary between scientific fields and course requirements, but it usually contains the following:

• Title: expresses the topic of your study
• Abstract: summarizes your research aims, methods, results, and conclusions
• Introduction: establishes the context needed to understand the topic
• Method: describes the materials and procedures used in the experiment
• Results: reports all descriptive and inferential statistical analyses
• Discussion: interprets and evaluates results and identifies limitations
• Conclusion: sums up the main findings of your experiment
• References: list of all sources cited using a specific style (e.g. APA)
• Appendices: contains lengthy materials, procedures, tables or figures

A lab report conveys the aim, methods, results, and conclusions of a scientific experiment . Lab reports are commonly assigned in science, technology, engineering, and mathematics (STEM) fields.

The abstract is the very last thing you write. You should only write it after your research is complete, so that you can accurately summarize the entirety of your thesis , dissertation or research paper .

If you’ve gone over the word limit set for your assignment, shorten your sentences and cut repetition and redundancy during the editing process. If you use a lot of long quotes , consider shortening them to just the essentials.

If you need to remove a lot of words, you may have to cut certain passages. Remember that everything in the text should be there to support your argument; look for any information that’s not essential to your point and remove it.

To make this process easier and faster, you can use a paraphrasing tool . With this tool, you can rewrite your text to make it simpler and shorter. If that’s not enough, you can copy-paste your paraphrased text into the summarizer . This tool will distill your text to its core message.

Revising, proofreading, and editing are different stages of the writing process .

• Revising is making structural and logical changes to your text—reformulating arguments and reordering information.
• Editing refers to making more local changes to things like sentence structure and phrasing to make sure your meaning is conveyed clearly and concisely.
• Proofreading involves looking at the text closely, line by line, to spot any typos and issues with consistency and correct them.

The literature review usually comes near the beginning of your thesis or dissertation . After the introduction , it grounds your research in a scholarly field and leads directly to your theoretical framework or methodology .

A literature review is a survey of scholarly sources (such as books, journal articles, and theses) related to a specific topic or research question .

It is often written as part of a thesis, dissertation , or research paper , in order to situate your work in relation to existing knowledge.

Avoid citing sources in your abstract . There are two reasons for this:

• The abstract should focus on your original research, not on the work of others.
• The abstract should be self-contained and fully understandable without reference to other sources.

There are some circumstances where you might need to mention other sources in an abstract: for example, if your research responds directly to another study or focuses on the work of a single theorist. In general, though, don’t include citations unless absolutely necessary.

An abstract is a concise summary of an academic text (such as a journal article or dissertation ). It serves two main purposes:

• To help potential readers determine the relevance of your paper for their own research.
• To communicate your key findings to those who don’t have time to read the whole paper.

Abstracts are often indexed along with keywords on academic databases, so they make your work more easily findable. Since the abstract is the first thing any reader sees, it’s important that it clearly and accurately summarizes the contents of your paper.

In a scientific paper, the methodology always comes after the introduction and before the results , discussion and conclusion . The same basic structure also applies to a thesis, dissertation , or research proposal .

Depending on the length and type of document, you might also include a literature review or theoretical framework before the methodology.

Whether you’re publishing a blog, submitting a research paper , or even just writing an important email, there are a few techniques you can use to make sure it’s error-free:

• Take a break : Set your work aside for at least a few hours so that you can look at it with fresh eyes.
• Proofread a printout : Staring at a screen for too long can cause fatigue – sit down with a pen and paper to check the final version.
• Use digital shortcuts : Take note of any recurring mistakes (for example, misspelling a particular word, switching between US and UK English , or inconsistently capitalizing a term), and use Find and Replace to fix it throughout the document.

If you want to be confident that an important text is error-free, it might be worth choosing a professional proofreading service instead.

Editing and proofreading are different steps in the process of revising a text.

Editing comes first, and can involve major changes to content, structure and language. The first stages of editing are often done by authors themselves, while a professional editor makes the final improvements to grammar and style (for example, by improving sentence structure and word choice ).

Proofreading is the final stage of checking a text before it is published or shared. It focuses on correcting minor errors and inconsistencies (for example, in punctuation and capitalization ). Proofreaders often also check for formatting issues, especially in print publishing.

The cost of proofreading depends on the type and length of text, the turnaround time, and the level of services required. Most proofreading companies charge per word or page, while freelancers sometimes charge an hourly rate.

For proofreading alone, which involves only basic corrections of typos and formatting mistakes, you might pay as little as $0.01 per word, but in many cases, your text will also require some level of editing , which costs slightly more.

It’s often possible to purchase combined proofreading and editing services and calculate the price in advance based on your requirements.

There are many different routes to becoming a professional proofreader or editor. The necessary qualifications depend on the field – to be an academic or scientific proofreader, for example, you will need at least a university degree in a relevant subject.

For most proofreading jobs, experience and demonstrated skills are more important than specific qualifications. Often your skills will be tested as part of the application process.

To learn practical proofreading skills, you can choose to take a course with a professional organization such as the Society for Editors and Proofreaders . Alternatively, you can apply to companies that offer specialized on-the-job training programmes, such as the Scribbr Academy .

Ask our team

Want to contact us directly? No problem.  We  are always here for you.

• Email [email protected]
• Start live chat
• Call +1 (510) 822-8066
• WhatsApp +31 20 261 6040

Our team helps students graduate by offering:

• A world-class citation generator
• Plagiarism Checker software powered by Turnitin
• Innovative Citation Checker software
• Professional proofreading services
• Over 300 helpful articles about academic writing, citing sources, plagiarism, and more

Scribbr specializes in editing study-related documents . We proofread:

• PhD dissertations
• Research proposals
• Personal statements
• Admission essays
• Motivation letters
• Reflection papers
• Journal articles
• Capstone projects

Scribbr’s Plagiarism Checker is powered by elements of Turnitin’s Similarity Checker , namely the plagiarism detection software and the Internet Archive and Premium Scholarly Publications content databases .

The add-on AI detector is powered by Scribbr’s proprietary software.

The Scribbr Citation Generator is developed using the open-source Citation Style Language (CSL) project and Frank Bennett’s citeproc-js . It’s the same technology used by dozens of other popular citation tools, including Mendeley and Zotero.

You can find all the citation styles and locales used in the Scribbr Citation Generator in our publicly accessible repository on Github .

Learn how to write a review of literature

What is a review of literature.

The format of a review of literature may vary from discipline to discipline and from assignment to assignment.

A review may be a self-contained unit — an end in itself — or a preface to and rationale for engaging in primary research. A review is a required part of grant and research proposals and often a chapter in theses and dissertations.

Generally, the purpose of a review is to analyze critically a segment of a published body of knowledge through summary, classification, and comparison of prior research studies, reviews of literature, and theoretical articles.

Writing the introduction

In the introduction, you should:

Define or identify the general topic, issue, or area of concern, thus providing an appropriate context for reviewing the literature.

Point out overall trends in what has been published about the topic; or conflicts in theory, methodology, evidence, and conclusions; or gaps in research and scholarship; or a single problem or new perspective of immediate interest.

Establish the writer’s reason (point of view) for reviewing the literature; explain the criteria to be used in analyzing and comparing literature and the organization of the review (sequence); and, when necessary, state why certain literature is or is not included (scope).

Writing the body

In the body, you should:

Group research studies and other types of literature (reviews, theoretical articles, case studies, etc.) according to common denominators such as qualitative versus quantitative approaches, conclusions of authors, specific purpose or objective, chronology, etc.

Summarize individual studies or articles with as much or as little detail as each merits according to its comparative importance in the literature, remembering that space (length) denotes significance.

Provide the reader with strong “umbrella” sentences at beginnings of paragraphs, “signposts” throughout, and brief “so what” summary sentences at intermediate points in the review to aid in understanding comparisons and analyses.

Writing the conclusion

In the conclusion, you should:

Summarize major contributions of significant studies and articles to the body of knowledge under review, maintaining the focus established in the introduction.

Evaluate the current “state of the art” for the body of knowledge reviewed, pointing out major methodological flaws or gaps in research, inconsistencies in theory and findings, and areas or issues pertinent to future study.

Conclude by providing some insight into the relationship between the central topic of the literature review and a larger area of study such as a discipline, a scientific endeavor, or a profession.

For further information see our handouts on Writing a Critical Review of a Nonfiction Book or Article or Reading a Book to Review It .

To learn more about literature reviews, take a look at our workshop on Writing Literature Reviews of Published Research.

Sample Literature Reviews

An important strategy for learning how to compose literature reviews in your field or within a specific genre is to locate and analyze representative examples. The following collection of annotated sample literature reviews written and co-written by colleagues associated with UW-Madison showcases how these reviews can do different kind of work for different purposes. Use these successful examples as a starting point for understanding how other writers have approached the challenging and important task of situating their idea in the context of established research.

• Sample 1 (PDF) A brief literature review within a political scientists’  National Science Foundation Graduate Research Fellowship  grant
• Sample 2 (PDF) A several-page literature review at the beginning of a published, academic article about philosophy
• Sample 3 (PDF) A brief literature review at the beginning of a published, academic article about photochemistry

Academic and Professional Writing

This is an accordion element with a series of buttons that open and close related content panels.

Analysis Papers

Reading Poetry

A Short Guide to Close Reading for Literary Analysis

Using Literary Quotations

Play Reviews

Writing a Rhetorical Précis to Analyze Nonfiction Texts

Incorporating Interview Data

Grant Proposals

Planning and Writing a Grant Proposal: The Basics

Additional Resources for Grants and Proposal Writing

Job Materials and Application Essays

Writing Personal Statements for Ph.D. Programs

• Before you begin: useful tips for writing your essay
• Guided brainstorming exercises
• Get more help with your essay
• Frequently Asked Questions

Resume Writing Tips

CV Writing Tips

Cover Letters

Business Letters

Proposals and Dissertations

Resources for Proposal Writers

Resources for Dissertators

Research Papers

Planning and Writing Research Papers

Quoting and Paraphrasing

Writing Annotated Bibliographies

Creating Poster Presentations

Writing an Abstract for Your Research Paper

Thank-You Notes

Advice for Students Writing Thank-You Notes to Donors

Reading for a Review

Critical Reviews

Writing a Review of Literature

Scientific Reports

Scientific Report Format

Sample Lab Assignment

Writing for the Web

Writing an Effective Blog Post

Writing for Social Media: A Guide for Academics

Information

• Author Services

Initiatives

You are accessing a machine-readable page. In order to be human-readable, please install an RSS reader.

All articles published by MDPI are made immediately available worldwide under an open access license. No special permission is required to reuse all or part of the article published by MDPI, including figures and tables. For articles published under an open access Creative Common CC BY license, any part of the article may be reused without permission provided that the original article is clearly cited. For more information, please refer to https://www.mdpi.com/openaccess .

Feature papers represent the most advanced research with significant potential for high impact in the field. A Feature Paper should be a substantial original Article that involves several techniques or approaches, provides an outlook for future research directions and describes possible research applications.

Feature papers are submitted upon individual invitation or recommendation by the scientific editors and must receive positive feedback from the reviewers.

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

Original Submission Date Received: .

• Active Journals
• Find a Journal
• Journal Proposal
• Proceedings Series
• For Authors
• For Reviewers
• For Editors
• For Librarians
• For Publishers
• For Societies
• For Conference Organizers
• Open Access Policy
• Institutional Open Access Program
• Special Issues Guidelines
• Editorial Process
• Research and Publication Ethics
• Article Processing Charges
• Testimonials
• Preprints.org
• SciProfiles
• Encyclopedia

Article Menu

• Subscribe SciFeed
• Google Scholar
• on Google Scholar
• Table of Contents

Find support for a specific problem in the support section of our website.

Please let us know what you think of our products and services.

Visit our dedicated information section to learn more about MDPI.

JSmol Viewer

Trigger point therapy techniques as an effective unconventional method of treating tension headaches: a systematic review.

1. Introduction

• Are various trigger points therapy techniques effective in treatment of tension-type headaches?
• How trigger points therapy affect physical and psychological variables in tension-type headaches?

2. Materials and Methods

2.1. eligibility criteria, 2.2. search strategy, 2.3. data extraction and evaluation of the methodological quality of studies, 4. discussion, 5. conclusions.

• Trigger point therapy has reduced the duration, intensity, and frequency of headaches.
• Dry needling, ischaemic compression, positional relaxation techniques, and massage protocols focused on deactivating trigger points are effective methods of unconventional treatment of tension-type headaches.

Author Contributions

Conflicts of interest.

• Anderson, R.E.; Seniscal, C. A Comparison of Selected Osteopathic Treatment and Relaxation for Tension-Type Headaches. Headache J. Head Face Pain 2006 , 46 , 1273–1280. [ Google Scholar ] [ CrossRef ]
• Stovner, L.; Hagen, K.; Jensen, R.; Katsarava, Z.; Lipton, R.; Scher, A.; Steiner, T.; Zwart, J.-A. The Global Burden of Headache: A Documentation of Headache Prevalence and Disability Worldwide. Cephalalgia 2007 , 27 , 193–210. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Global Burden of Disease Study 2013 Collaborators Global, Regional, and National Incidence, Prevalence, and Years Lived with Disability for 301 Acute and Chronic Diseases and Injuries in 188 Countries, 1990–2013: A Systematic Analysis for the Global Burden of Disease Study 2013. Lancet 2015 , 386 , 743–800. [ CrossRef ]
• Stovner, L.J.; Andrée, C. Impact of Headache in Europe: A Review for the Eurolight Project. J. Headache Pain 2008 , 9 , 139–146. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Sacco, S.; Ricci, S.; Carolei, A. Tension-Type Headache and Systemic Medical Disorders. Curr. Pain Headache Rep. 2011 , 15 , 438–443. [ Google Scholar ] [ CrossRef ]
• Loder, E.; Rizzoli, P. Tension-Type Headache. BMJ 2008 , 336 , 88–92. [ Google Scholar ] [ CrossRef ]
• Do, T.P.; Heldarskard, G.F.; Kolding, L.T.; Hvedstrup, J.; Schytz, H.W. Myofascial Trigger Points in Migraine and Tension-Type Headache. J. Headache Pain 2018 , 19 , 84. [ Google Scholar ] [ CrossRef ]
• Simons, D.G.; Travell, J.G.; Simons, L.S. Travell & Simons’ Myofascial Pain and Dysfunction: Upper Half of Body ; Lippincott Williams & Wilkins: Philadelphia, PA, USA, 1999; ISBN 978-0-683-08363-7. [ Google Scholar ]
• Bron, C.; Dommerholt, J.D. Etiology of Myofascial Trigger Points. Curr. Pain Headache Rep. 2012 , 16 , 439–444. [ Google Scholar ] [ CrossRef ]
• Shah, J.P.; Gilliams, E.A. Uncovering the Biochemical Milieu of Myofascial Trigger Points Using in Vivo Microdialysis: An Application of Muscle Pain Concepts to Myofascial Pain Syndrome. J. Bodyw. Mov. Ther. 2008 , 12 , 371–384. [ Google Scholar ] [ CrossRef ]
• Woolf, C.J. Central Sensitization: Implications for the Diagnosis and Treatment of Pain. Pain 2011 , 152 , S2–S15. [ Google Scholar ] [ CrossRef ]
• Fernández-de-Las-Peñas, C.; Ge, H.-Y.; Alonso-Blanco, C.; González-Iglesias, J.; Arendt-Nielsen, L. Referred Pain Areas of Active Myofascial Trigger Points in Head, Neck, and Shoulder Muscles, in Chronic Tension Type Headache. J. Bodyw. Mov. Ther. 2010 , 14 , 391–396. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Victoria Espí-López, G.; Arnal-Gómez, A.; Arbós-Berenguer, T.; González, Á.A.L.; Vicente-Herrero, T. Effectiveness of Physical Therapy in Patients with Tension-Type Headache: Literature Review. J. Jpn. Phys. Ther. Assoc. 2014 , 17 , 31–38. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Castien, R.F.; van der Windt, D.A.W.M.; Grooten, A.; Dekker, J. Effectiveness of Manual Therapy for Chronic Tension-Type Headache: A Pragmatic, Randomised, Clinical Trial. Cephalalgia 2011 , 31 , 133–143. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Page, M.J.; McKenzie, J.E.; Bossuyt, P.M.; Boutron, I.; Hoffmann, T.C.; Mulrow, C.D.; Shamseer, L.; Tetzlaff, J.M.; Akl, E.A.; Brennan, S.E.; et al. The PRISMA 2020 Statement: An Updated Guideline for Reporting Systematic Reviews. BMJ 2021 , 372 , n71. [ Google Scholar ] [ CrossRef ]
• Santos, C.M.d.C.; Pimenta, C.A.d.M.; Nobre, M.R.C. The PICO Strategy for the Research Question Construction and Evidence Search. Rev. Lat.-Am. Enferm. 2007 , 15 , 508–511. [ Google Scholar ] [ CrossRef ]
• Nakandala, P.; Nanayakkara, I.; Wadugodapitiya, S.; Gawarammana, I. The Efficacy of Physiotherapy Interventions in the Treatment of Adhesive Capsulitis: A Systematic Review. J. Back Musculoskelet. Rehabil. 2021 , 34 , 195–205. [ Google Scholar ] [ CrossRef ]
• Zieliński, G.; Pająk-Zielińska, B.; Ginszt, M. A Meta-Analysis of the Global Prevalence of Temporomandibular Disorders. J. Clin. Med. 2024 , 13 , 1365. [ Google Scholar ] [ CrossRef ]
• Moseley, A.M.; Elkins, M.R.; Van der Wees, P.J.; Pinheiro, M.B. Using Research to Guide Practice: The Physiotherapy Evidence Database (PEDro). Braz. J. Phys. Ther. 2020 , 24 , 384–391. [ Google Scholar ] [ CrossRef ]
• Zieliński, G.; Pająk, A.; Wójcicki, M. Global Prevalence of Sleep Bruxism and Awake Bruxism in Pediatric and Adult Populations: A Systematic Review and Meta-Analysis. J. Clin. Med. 2024 , 13 , 4259. [ Google Scholar ] [ CrossRef ]
• de Morton, N.A. The PEDro Scale Is a Valid Measure of the Methodological Quality of Clinical Trials: A Demographic Study. Aust. J. Physiother. 2009 , 55 , 129–133. [ Google Scholar ] [ CrossRef ]
• Centre for Evidence-Based Medicine. Oxford Centre for Evidence-Based Medicine—Levels of Evidence. Available online: http://www.cebm.net/Oxford-Centre-Evidence-Based-Medicine-Levelsevidence-March-2009/ (accessed on 13 June 2022).
• Abaschian, F.; Mansoursohani, S.; Togha, M.; Yassin, M.; Abadi, L. The Investigation of the Effects of Deep Dry Needling into Trigger Points of Temporalis, Sternocleidomastoid and Upper Trapezius on Females with Episodic Tension Type Headache. Res. Bull. Med. Sci. 2020 , 25 , e6. [ Google Scholar ]
• Berggreen, S.; Wiik, E.; Lund, H. Treatment of Myofascial Trigger Points in Female Patients with Chronic Tension-Type Headache—A Randomized Controlled Trial. Adv. Physiother. 2012 , 14 , 10–17. [ Google Scholar ] [ CrossRef ]
• Gildir, S.; Tüzün, E.H.; Eroğlu, G.; Eker, L. A Randomized Trial of Trigger Point Dry Needling versus Sham Needling for Chronic Tension-Type Headache. Medicine 2019 , 98 , e14520. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Kamali, F.; Mohamadi, M.; Fakheri, L.; Mohammadnejad, F. Dry Needling versus Friction Massage to Treat Tension Type Headache: A Randomized Clinical Trial. J. Bodyw. Mov. Ther. 2019 , 23 , 89–93. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Mohamadi, M.; Ghanbari, A.; Rahimi Jaberi, A. Tension—Type—Headache Treated by Positional Release Therapy: A Case Report. Man. Ther. 2012 , 17 , 456–458. [ Google Scholar ] [ CrossRef ]
• Mohamadi, M.; Rojhani-Shirazi, Z.; Assadsangabi, R.; Rahimi-Jaberi, A. Can the Positional Release Technique Affect Central Sensitization in Patients With Chronic Tension-Type Headache? A Randomized Clinical Trial. Arch. Phys. Med. Rehabil. 2020 , 101 , 1696–1703. [ Google Scholar ] [ CrossRef ]
• Moraska, A.; Chandler, C. Changes in Clinical Parameters in Patients with Tension-Type Headache Following Massage Therapy: A Pilot Study. J. Man. Manip. Ther. 2008 , 16 , 106–112. [ Google Scholar ] [ CrossRef ]
• Moraska, A.F.; Stenerson, L.; Butryn, N.; Krutsch, J.P.; Schmiege, S.J.; Mann, J.D. Myofascial Trigger Point-Focused Head and Neck Massage for Recurrent Tension-Type Headache: A Randomized, Placebo-Controlled Clinical Trial. Clin. J. Pain 2015 , 31 , 159–168. [ Google Scholar ] [ CrossRef ]
• von Stülpnagel, C.; Reilich, P.; Straube, A.; Schäfer, J.; Blaschek, A.; Lee, S.-H.; Müller-Felber, W.; Henschel, V.; Mansmann, U.; Heinen, F. Myofascial Trigger Points in Children with Tension-Type Headache: A New Diagnostic and Therapeutic Option. J. Child Neurol. 2009 , 24 , 406–409. [ Google Scholar ] [ CrossRef ]
• Freitag, F. Managing and Treating Tension-Type Headache. Med. Clin. N. Am. 2013 , 97 , 281–292. [ Google Scholar ] [ CrossRef ]
• Lozano López, C.; Mesa Jiménez, J.; de la Hoz Aizpurúa, J.L.; Pareja Grande, J.; Fernández de las Peñas, C. Efficacy of Manual Therapy in the Treatment of Tension-Type Headache. A Systematic Review from 2000 to 2013. Neurología 2016 , 31 , 357–369. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Fernández-de-Las-Peñas, C.; Cuadrado, M.L. Physical Therapy for Headaches. Cephalalgia 2016 , 36 , 1134–1142. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• American Physical Therapy Association. Physical Therapists & the Performance of Dry Needling: An Educational Resource Paper ; American Physical Therapy Association: Alexandria, VA, USA, 2012. [ Google Scholar ]
• Tough, E.A.; White, A.R.; Richards, S.; Campbell, J. Variability of Criteria Used to Diagnose Myofascial Trigger Point Pain Syndrome--Evidence from a Review of the Literature. Clin. J. Pain 2007 , 23 , 278–286. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Gemmell, H.; Miller, P.; Nordstrom, H. Immediate Effect of Ischaemic Compression and Trigger Point Pressure Release on Neck Pain and Upper Trapezius Trigger Points: A Randomised Controlled Trial. Clin. Chiropr. 2008 , 11 , 30–36. [ Google Scholar ] [ CrossRef ]
• Hou, C.-R.; Tsai, L.-C.; Cheng, K.-F.; Chung, K.-C.; Hong, C.-Z. Immediate Effects of Various Physical Therapeutic Modalities on Cervical Myofascial Pain and Trigger-Point Sensitivity. Arch. Phys. Med. Rehabil. 2002 , 83 , 1406–1414. [ Google Scholar ]
• Boon, S. Strain-Counterstrain Phenomenon in Skeletal Muscle and Appropriate Therapeutic Intervention. Assoc. Health Phys. Educ. Recreat. 1990 , 3 , 41–48. [ Google Scholar ]
• Cortese, K.; Tagliatti, E.; Gagliani, M.C.; Frascio, M.; Zarcone, D.; Raposio, E. Ultrastructural Imaging Reveals Vascular Remodeling in Migraine Patients. Histochem. Cell Biol. 2022 , 157 , 459–465. [ Google Scholar ] [ CrossRef ]
• Raposio, E.; Raposio, G.; Del Duchetto, D.; Tagliatti, E.; Cortese, K. Morphologic Vascular Anomalies Detected during Migraine Surgery. J. Plast. Reconstr. Aesthetic Surg. 2022 , 75 , 4069–4073. [ Google Scholar ] [ CrossRef ]
• Arendt-Nielsen, L.; Svensson, P. Referred Muscle Pain: Basic and Clinical Findings. Clin. J. Pain 2001 , 17 , 11–19. [ Google Scholar ] [ CrossRef ]
• Travell, J.G.; Simons, D.G. Myofascial Pain and Dysfunction: The Trigger Point Manual ; Williams & Wilkins: Baltimore, MA, USA, 1999; ISBN 978-0-683-08366-8. [ Google Scholar ]
• Fernández-de-las-Peñas, C.; Cuadrado, M.L.; Arendt-Nielsen, L.; Simons, D.G.; Pareja, J.A. Myofascial Trigger Points and Sensitization: An Updated Pain Model for Tension-Type Headache. Cephalalgia 2007 , 27 , 383–393. [ Google Scholar ] [ CrossRef ]
• Schmidt-Hansen, P.T.; Svensson, P.; Jensen, T.S.; Graven-Nielsen, T.; Bach, F.W. Patterns of Experimentally Induced Pain in Pericranial Muscles. Cephalalgia 2006 , 26 , 568–577. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Fernández-de-las-Peñas, C.; Fernández-Mayoralas, D.M.; Ortega-Santiago, R.; Ambite-Quesada, S.; Palacios-Ceña, D.; Pareja, J.A. Referred Pain from Myofascial Trigger Points in Head and Neck-Shoulder Muscles Reproduces Head Pain Features in Children with Chronic Tension Type Headache. J. Headache Pain 2011 , 12 , 35–43. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Fernández-de-las-Peñas, C.; Alonso-Blanco, C.; Cuadrado, M.L.; Gerwin, R.D.; Pareja, J.A. Trigger Points in the Suboccipital Muscles and Forward Head Posture in Tension-Type Headache. Headache J. Head Face Pain 2006 , 46 , 454–460. [ Google Scholar ] [ CrossRef ]
• Fernández-de-Las-Peñas, C. Myofascial Head Pain. Curr. Pain Headache Rep. 2015 , 19 , 28. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Alonso-Blanco, C.; de-la-Llave-Rincón, A.I.; Fernández-de-las-Peñas, C. Muscle Trigger Point Therapy in Tension-Type Headache. Expert Rev. Neurother. 2012 , 12 , 315–322. [ Google Scholar ] [ CrossRef ]
• Sohn, J.-H.; Choi, H.-C.; Lee, S.-M.; Jun, A.-Y. Differences in Cervical Musculoskeletal Impairment between Episodic and Chronic Tension-Type Headache. Cephalalgia 2010 , 30 , 1514–1523. [ Google Scholar ] [ CrossRef ]
• Gerwin, R.D.; Dommerholt, J.; Shah, J.P. An Expansion of Simons’ Integrated Hypothesis of Trigger Point Formation. Curr. Pain Headache Rep. 2004 , 8 , 468–475. [ Google Scholar ] [ CrossRef ]
• Arendt-Nielsen, L.; Morlion, B.; Perrot, S.; Dahan, A.; Dickenson, A.; Kress, H.G.; Wells, C.; Bouhassira, D.; Drewes, A.M. Assessment and Manifestation of Central Sensitisation across Different Chronic Pain Conditions. Eur. J. Pain 2018 , 22 , 216–241. [ Google Scholar ] [ CrossRef ]
• van Griensven, H.; Schmid, A.; Trendafilova, T.; Low, M. Central Sensitization in Musculoskeletal Pain: Lost in Translation? J. Orthop. Sports Phys. Ther. 2020 , 50 , 592–596. [ Google Scholar ] [ CrossRef ]
• Fernández-de-Las-Peñas, C.; Alonso-Blanco, C.; Cuadrado, M.L.; Gerwin, R.D.; Pareja, J.A. Myofascial Trigger Points and Their Relationship to Headache Clinical Parameters in Chronic Tension-Type Headache. Headache J. Head Face Pain 2006 , 46 , 1264–1272. [ Google Scholar ] [ CrossRef ]
• Nystrom, N.; Freeman, M. Central Sensitization Is Modulated Following Trigger Point Anesthetization in Patients with Chronic Pain from Whiplash Trauma. A Double-Blind, Placebo-Controlled, Crossover Study. Pain Med. 2017 , 19 , 124–129. [ Google Scholar ] [ CrossRef ]

Click here to enlarge figure

Share and Cite

Dolina, A.; Baszczowski, M.; Wilkowicz, W.; Zieliński, G.; Szkutnik, J.; Gawda, P. Trigger Point Therapy Techniques as an Effective Unconventional Method of Treating Tension Headaches: A Systematic Review. Healthcare 2024 , 12 , 1868. https://doi.org/10.3390/healthcare12181868

Dolina A, Baszczowski M, Wilkowicz W, Zieliński G, Szkutnik J, Gawda P. Trigger Point Therapy Techniques as an Effective Unconventional Method of Treating Tension Headaches: A Systematic Review. Healthcare . 2024; 12(18):1868. https://doi.org/10.3390/healthcare12181868

Dolina, Aleksandra, Michał Baszczowski, Wiktor Wilkowicz, Grzegorz Zieliński, Jacek Szkutnik, and Piotr Gawda. 2024. "Trigger Point Therapy Techniques as an Effective Unconventional Method of Treating Tension Headaches: A Systematic Review" Healthcare 12, no. 18: 1868. https://doi.org/10.3390/healthcare12181868

Article Metrics

Article access statistics, further information, mdpi initiatives, follow mdpi.

Subscribe to receive issue release notifications and newsletters from MDPI journals

Warning: The NCBI web site requires JavaScript to function. more...

An official website of the United States government

The .gov means it's official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings
• Browse Titles

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

Lau F, Kuziemsky C, editors. Handbook of eHealth Evaluation: An Evidence-based Approach [Internet]. Victoria (BC): University of Victoria; 2017 Feb 27.

Handbook of eHealth Evaluation: An Evidence-based Approach [Internet].

Chapter 9 methods for literature reviews.

Guy Paré and Spyros Kitsiou .

9.1. Introduction

Literature reviews play a critical role in scholarship because science remains, first and foremost, a cumulative endeavour ( vom Brocke et al., 2009 ). As in any academic discipline, rigorous knowledge syntheses are becoming indispensable in keeping up with an exponentially growing eHealth literature, assisting practitioners, academics, and graduate students in finding, evaluating, and synthesizing the contents of many empirical and conceptual papers. Among other methods, literature reviews are essential for: (a) identifying what has been written on a subject or topic; (b) determining the extent to which a specific research area reveals any interpretable trends or patterns; (c) aggregating empirical findings related to a narrow research question to support evidence-based practice; (d) generating new frameworks and theories; and (e) identifying topics or questions requiring more investigation ( Paré, Trudel, Jaana, & Kitsiou, 2015 ).

Literature reviews can take two major forms. The most prevalent one is the “literature review” or “background” section within a journal paper or a chapter in a graduate thesis. This section synthesizes the extant literature and usually identifies the gaps in knowledge that the empirical study addresses ( Sylvester, Tate, & Johnstone, 2013 ). It may also provide a theoretical foundation for the proposed study, substantiate the presence of the research problem, justify the research as one that contributes something new to the cumulated knowledge, or validate the methods and approaches for the proposed study ( Hart, 1998 ; Levy & Ellis, 2006 ).

The second form of literature review, which is the focus of this chapter, constitutes an original and valuable work of research in and of itself ( Paré et al., 2015 ). Rather than providing a base for a researcher’s own work, it creates a solid starting point for all members of the community interested in a particular area or topic ( Mulrow, 1987 ). The so-called “review article” is a journal-length paper which has an overarching purpose to synthesize the literature in a field, without collecting or analyzing any primary data ( Green, Johnson, & Adams, 2006 ).

When appropriately conducted, review articles represent powerful information sources for practitioners looking for state-of-the art evidence to guide their decision-making and work practices ( Paré et al., 2015 ). Further, high-quality reviews become frequently cited pieces of work which researchers seek out as a first clear outline of the literature when undertaking empirical studies ( Cooper, 1988 ; Rowe, 2014 ). Scholars who track and gauge the impact of articles have found that review papers are cited and downloaded more often than any other type of published article ( Cronin, Ryan, & Coughlan, 2008 ; Montori, Wilczynski, Morgan, Haynes, & Hedges, 2003 ; Patsopoulos, Analatos, & Ioannidis, 2005 ). The reason for their popularity may be the fact that reading the review enables one to have an overview, if not a detailed knowledge of the area in question, as well as references to the most useful primary sources ( Cronin et al., 2008 ). Although they are not easy to conduct, the commitment to complete a review article provides a tremendous service to one’s academic community ( Paré et al., 2015 ; Petticrew & Roberts, 2006 ). Most, if not all, peer-reviewed journals in the fields of medical informatics publish review articles of some type.

The main objectives of this chapter are fourfold: (a) to provide an overview of the major steps and activities involved in conducting a stand-alone literature review; (b) to describe and contrast the different types of review articles that can contribute to the eHealth knowledge base; (c) to illustrate each review type with one or two examples from the eHealth literature; and (d) to provide a series of recommendations for prospective authors of review articles in this domain.

9.2. Overview of the Literature Review Process and Steps

As explained in Templier and Paré (2015) , there are six generic steps involved in conducting a review article:

• formulating the research question(s) and objective(s),
• searching the extant literature,
• screening for inclusion,
• assessing the quality of primary studies,
• extracting data, and
• analyzing data.

Although these steps are presented here in sequential order, one must keep in mind that the review process can be iterative and that many activities can be initiated during the planning stage and later refined during subsequent phases ( Finfgeld-Connett & Johnson, 2013 ; Kitchenham & Charters, 2007 ).

Formulating the research question(s) and objective(s): As a first step, members of the review team must appropriately justify the need for the review itself ( Petticrew & Roberts, 2006 ), identify the review’s main objective(s) ( Okoli & Schabram, 2010 ), and define the concepts or variables at the heart of their synthesis ( Cooper & Hedges, 2009 ; Webster & Watson, 2002 ). Importantly, they also need to articulate the research question(s) they propose to investigate ( Kitchenham & Charters, 2007 ). In this regard, we concur with Jesson, Matheson, and Lacey (2011) that clearly articulated research questions are key ingredients that guide the entire review methodology; they underscore the type of information that is needed, inform the search for and selection of relevant literature, and guide or orient the subsequent analysis. Searching the extant literature: The next step consists of searching the literature and making decisions about the suitability of material to be considered in the review ( Cooper, 1988 ). There exist three main coverage strategies. First, exhaustive coverage means an effort is made to be as comprehensive as possible in order to ensure that all relevant studies, published and unpublished, are included in the review and, thus, conclusions are based on this all-inclusive knowledge base. The second type of coverage consists of presenting materials that are representative of most other works in a given field or area. Often authors who adopt this strategy will search for relevant articles in a small number of top-tier journals in a field ( Paré et al., 2015 ). In the third strategy, the review team concentrates on prior works that have been central or pivotal to a particular topic. This may include empirical studies or conceptual papers that initiated a line of investigation, changed how problems or questions were framed, introduced new methods or concepts, or engendered important debate ( Cooper, 1988 ). Screening for inclusion: The following step consists of evaluating the applicability of the material identified in the preceding step ( Levy & Ellis, 2006 ; vom Brocke et al., 2009 ). Once a group of potential studies has been identified, members of the review team must screen them to determine their relevance ( Petticrew & Roberts, 2006 ). A set of predetermined rules provides a basis for including or excluding certain studies. This exercise requires a significant investment on the part of researchers, who must ensure enhanced objectivity and avoid biases or mistakes. As discussed later in this chapter, for certain types of reviews there must be at least two independent reviewers involved in the screening process and a procedure to resolve disagreements must also be in place ( Liberati et al., 2009 ; Shea et al., 2009 ). Assessing the quality of primary studies: In addition to screening material for inclusion, members of the review team may need to assess the scientific quality of the selected studies, that is, appraise the rigour of the research design and methods. Such formal assessment, which is usually conducted independently by at least two coders, helps members of the review team refine which studies to include in the final sample, determine whether or not the differences in quality may affect their conclusions, or guide how they analyze the data and interpret the findings ( Petticrew & Roberts, 2006 ). Ascribing quality scores to each primary study or considering through domain-based evaluations which study components have or have not been designed and executed appropriately makes it possible to reflect on the extent to which the selected study addresses possible biases and maximizes validity ( Shea et al., 2009 ). Extracting data: The following step involves gathering or extracting applicable information from each primary study included in the sample and deciding what is relevant to the problem of interest ( Cooper & Hedges, 2009 ). Indeed, the type of data that should be recorded mainly depends on the initial research questions ( Okoli & Schabram, 2010 ). However, important information may also be gathered about how, when, where and by whom the primary study was conducted, the research design and methods, or qualitative/quantitative results ( Cooper & Hedges, 2009 ). Analyzing and synthesizing data : As a final step, members of the review team must collate, summarize, aggregate, organize, and compare the evidence extracted from the included studies. The extracted data must be presented in a meaningful way that suggests a new contribution to the extant literature ( Jesson et al., 2011 ). Webster and Watson (2002) warn researchers that literature reviews should be much more than lists of papers and should provide a coherent lens to make sense of extant knowledge on a given topic. There exist several methods and techniques for synthesizing quantitative (e.g., frequency analysis, meta-analysis) and qualitative (e.g., grounded theory, narrative analysis, meta-ethnography) evidence ( Dixon-Woods, Agarwal, Jones, Young, & Sutton, 2005 ; Thomas & Harden, 2008 ).

9.3. Types of Review Articles and Brief Illustrations

EHealth researchers have at their disposal a number of approaches and methods for making sense out of existing literature, all with the purpose of casting current research findings into historical contexts or explaining contradictions that might exist among a set of primary research studies conducted on a particular topic. Our classification scheme is largely inspired from Paré and colleagues’ (2015) typology. Below we present and illustrate those review types that we feel are central to the growth and development of the eHealth domain.

9.3.1. Narrative Reviews

The narrative review is the “traditional” way of reviewing the extant literature and is skewed towards a qualitative interpretation of prior knowledge ( Sylvester et al., 2013 ). Put simply, a narrative review attempts to summarize or synthesize what has been written on a particular topic but does not seek generalization or cumulative knowledge from what is reviewed ( Davies, 2000 ; Green et al., 2006 ). Instead, the review team often undertakes the task of accumulating and synthesizing the literature to demonstrate the value of a particular point of view ( Baumeister & Leary, 1997 ). As such, reviewers may selectively ignore or limit the attention paid to certain studies in order to make a point. In this rather unsystematic approach, the selection of information from primary articles is subjective, lacks explicit criteria for inclusion and can lead to biased interpretations or inferences ( Green et al., 2006 ). There are several narrative reviews in the particular eHealth domain, as in all fields, which follow such an unstructured approach ( Silva et al., 2015 ; Paul et al., 2015 ).

Despite these criticisms, this type of review can be very useful in gathering together a volume of literature in a specific subject area and synthesizing it. As mentioned above, its primary purpose is to provide the reader with a comprehensive background for understanding current knowledge and highlighting the significance of new research ( Cronin et al., 2008 ). Faculty like to use narrative reviews in the classroom because they are often more up to date than textbooks, provide a single source for students to reference, and expose students to peer-reviewed literature ( Green et al., 2006 ). For researchers, narrative reviews can inspire research ideas by identifying gaps or inconsistencies in a body of knowledge, thus helping researchers to determine research questions or formulate hypotheses. Importantly, narrative reviews can also be used as educational articles to bring practitioners up to date with certain topics of issues ( Green et al., 2006 ).

Recently, there have been several efforts to introduce more rigour in narrative reviews that will elucidate common pitfalls and bring changes into their publication standards. Information systems researchers, among others, have contributed to advancing knowledge on how to structure a “traditional” review. For instance, Levy and Ellis (2006) proposed a generic framework for conducting such reviews. Their model follows the systematic data processing approach comprised of three steps, namely: (a) literature search and screening; (b) data extraction and analysis; and (c) writing the literature review. They provide detailed and very helpful instructions on how to conduct each step of the review process. As another methodological contribution, vom Brocke et al. (2009) offered a series of guidelines for conducting literature reviews, with a particular focus on how to search and extract the relevant body of knowledge. Last, Bandara, Miskon, and Fielt (2011) proposed a structured, predefined and tool-supported method to identify primary studies within a feasible scope, extract relevant content from identified articles, synthesize and analyze the findings, and effectively write and present the results of the literature review. We highly recommend that prospective authors of narrative reviews consult these useful sources before embarking on their work.

Darlow and Wen (2015) provide a good example of a highly structured narrative review in the eHealth field. These authors synthesized published articles that describe the development process of mobile health (m-health) interventions for patients’ cancer care self-management. As in most narrative reviews, the scope of the research questions being investigated is broad: (a) how development of these systems are carried out; (b) which methods are used to investigate these systems; and (c) what conclusions can be drawn as a result of the development of these systems. To provide clear answers to these questions, a literature search was conducted on six electronic databases and Google Scholar . The search was performed using several terms and free text words, combining them in an appropriate manner. Four inclusion and three exclusion criteria were utilized during the screening process. Both authors independently reviewed each of the identified articles to determine eligibility and extract study information. A flow diagram shows the number of studies identified, screened, and included or excluded at each stage of study selection. In terms of contributions, this review provides a series of practical recommendations for m-health intervention development.

9.3.2. Descriptive or Mapping Reviews

The primary goal of a descriptive review is to determine the extent to which a body of knowledge in a particular research topic reveals any interpretable pattern or trend with respect to pre-existing propositions, theories, methodologies or findings ( King & He, 2005 ; Paré et al., 2015 ). In contrast with narrative reviews, descriptive reviews follow a systematic and transparent procedure, including searching, screening and classifying studies ( Petersen, Vakkalanka, & Kuzniarz, 2015 ). Indeed, structured search methods are used to form a representative sample of a larger group of published works ( Paré et al., 2015 ). Further, authors of descriptive reviews extract from each study certain characteristics of interest, such as publication year, research methods, data collection techniques, and direction or strength of research outcomes (e.g., positive, negative, or non-significant) in the form of frequency analysis to produce quantitative results ( Sylvester et al., 2013 ). In essence, each study included in a descriptive review is treated as the unit of analysis and the published literature as a whole provides a database from which the authors attempt to identify any interpretable trends or draw overall conclusions about the merits of existing conceptualizations, propositions, methods or findings ( Paré et al., 2015 ). In doing so, a descriptive review may claim that its findings represent the state of the art in a particular domain ( King & He, 2005 ).

In the fields of health sciences and medical informatics, reviews that focus on examining the range, nature and evolution of a topic area are described by Anderson, Allen, Peckham, and Goodwin (2008) as mapping reviews . Like descriptive reviews, the research questions are generic and usually relate to publication patterns and trends. There is no preconceived plan to systematically review all of the literature although this can be done. Instead, researchers often present studies that are representative of most works published in a particular area and they consider a specific time frame to be mapped.

An example of this approach in the eHealth domain is offered by DeShazo, Lavallie, and Wolf (2009). The purpose of this descriptive or mapping review was to characterize publication trends in the medical informatics literature over a 20-year period (1987 to 2006). To achieve this ambitious objective, the authors performed a bibliometric analysis of medical informatics citations indexed in medline using publication trends, journal frequencies, impact factors, Medical Subject Headings (MeSH) term frequencies, and characteristics of citations. Findings revealed that there were over 77,000 medical informatics articles published during the covered period in numerous journals and that the average annual growth rate was 12%. The MeSH term analysis also suggested a strong interdisciplinary trend. Finally, average impact scores increased over time with two notable growth periods. Overall, patterns in research outputs that seem to characterize the historic trends and current components of the field of medical informatics suggest it may be a maturing discipline (DeShazo et al., 2009).

9.3.3. Scoping Reviews

Scoping reviews attempt to provide an initial indication of the potential size and nature of the extant literature on an emergent topic (Arksey & O’Malley, 2005; Daudt, van Mossel, & Scott, 2013 ; Levac, Colquhoun, & O’Brien, 2010). A scoping review may be conducted to examine the extent, range and nature of research activities in a particular area, determine the value of undertaking a full systematic review (discussed next), or identify research gaps in the extant literature ( Paré et al., 2015 ). In line with their main objective, scoping reviews usually conclude with the presentation of a detailed research agenda for future works along with potential implications for both practice and research.

Unlike narrative and descriptive reviews, the whole point of scoping the field is to be as comprehensive as possible, including grey literature (Arksey & O’Malley, 2005). Inclusion and exclusion criteria must be established to help researchers eliminate studies that are not aligned with the research questions. It is also recommended that at least two independent coders review abstracts yielded from the search strategy and then the full articles for study selection ( Daudt et al., 2013 ). The synthesized evidence from content or thematic analysis is relatively easy to present in tabular form (Arksey & O’Malley, 2005; Thomas & Harden, 2008 ).

One of the most highly cited scoping reviews in the eHealth domain was published by Archer, Fevrier-Thomas, Lokker, McKibbon, and Straus (2011) . These authors reviewed the existing literature on personal health record ( phr ) systems including design, functionality, implementation, applications, outcomes, and benefits. Seven databases were searched from 1985 to March 2010. Several search terms relating to phr s were used during this process. Two authors independently screened titles and abstracts to determine inclusion status. A second screen of full-text articles, again by two independent members of the research team, ensured that the studies described phr s. All in all, 130 articles met the criteria and their data were extracted manually into a database. The authors concluded that although there is a large amount of survey, observational, cohort/panel, and anecdotal evidence of phr benefits and satisfaction for patients, more research is needed to evaluate the results of phr implementations. Their in-depth analysis of the literature signalled that there is little solid evidence from randomized controlled trials or other studies through the use of phr s. Hence, they suggested that more research is needed that addresses the current lack of understanding of optimal functionality and usability of these systems, and how they can play a beneficial role in supporting patient self-management ( Archer et al., 2011 ).

9.3.4. Forms of Aggregative Reviews

Healthcare providers, practitioners, and policy-makers are nowadays overwhelmed with large volumes of information, including research-based evidence from numerous clinical trials and evaluation studies, assessing the effectiveness of health information technologies and interventions ( Ammenwerth & de Keizer, 2004 ; Deshazo et al., 2009 ). It is unrealistic to expect that all these disparate actors will have the time, skills, and necessary resources to identify the available evidence in the area of their expertise and consider it when making decisions. Systematic reviews that involve the rigorous application of scientific strategies aimed at limiting subjectivity and bias (i.e., systematic and random errors) can respond to this challenge.

Systematic reviews attempt to aggregate, appraise, and synthesize in a single source all empirical evidence that meet a set of previously specified eligibility criteria in order to answer a clearly formulated and often narrow research question on a particular topic of interest to support evidence-based practice ( Liberati et al., 2009 ). They adhere closely to explicit scientific principles ( Liberati et al., 2009 ) and rigorous methodological guidelines (Higgins & Green, 2008) aimed at reducing random and systematic errors that can lead to deviations from the truth in results or inferences. The use of explicit methods allows systematic reviews to aggregate a large body of research evidence, assess whether effects or relationships are in the same direction and of the same general magnitude, explain possible inconsistencies between study results, and determine the strength of the overall evidence for every outcome of interest based on the quality of included studies and the general consistency among them ( Cook, Mulrow, & Haynes, 1997 ). The main procedures of a systematic review involve:

• Formulating a review question and developing a search strategy based on explicit inclusion criteria for the identification of eligible studies (usually described in the context of a detailed review protocol).
• Searching for eligible studies using multiple databases and information sources, including grey literature sources, without any language restrictions.
• Selecting studies, extracting data, and assessing risk of bias in a duplicate manner using two independent reviewers to avoid random or systematic errors in the process.
• Analyzing data using quantitative or qualitative methods.
• Presenting results in summary of findings tables.
• Interpreting results and drawing conclusions.

Many systematic reviews, but not all, use statistical methods to combine the results of independent studies into a single quantitative estimate or summary effect size. Known as meta-analyses , these reviews use specific data extraction and statistical techniques (e.g., network, frequentist, or Bayesian meta-analyses) to calculate from each study by outcome of interest an effect size along with a confidence interval that reflects the degree of uncertainty behind the point estimate of effect ( Borenstein, Hedges, Higgins, & Rothstein, 2009 ; Deeks, Higgins, & Altman, 2008 ). Subsequently, they use fixed or random-effects analysis models to combine the results of the included studies, assess statistical heterogeneity, and calculate a weighted average of the effect estimates from the different studies, taking into account their sample sizes. The summary effect size is a value that reflects the average magnitude of the intervention effect for a particular outcome of interest or, more generally, the strength of a relationship between two variables across all studies included in the systematic review. By statistically combining data from multiple studies, meta-analyses can create more precise and reliable estimates of intervention effects than those derived from individual studies alone, when these are examined independently as discrete sources of information.

The review by Gurol-Urganci, de Jongh, Vodopivec-Jamsek, Atun, and Car (2013) on the effects of mobile phone messaging reminders for attendance at healthcare appointments is an illustrative example of a high-quality systematic review with meta-analysis. Missed appointments are a major cause of inefficiency in healthcare delivery with substantial monetary costs to health systems. These authors sought to assess whether mobile phone-based appointment reminders delivered through Short Message Service ( sms ) or Multimedia Messaging Service ( mms ) are effective in improving rates of patient attendance and reducing overall costs. To this end, they conducted a comprehensive search on multiple databases using highly sensitive search strategies without language or publication-type restrictions to identify all rct s that are eligible for inclusion. In order to minimize the risk of omitting eligible studies not captured by the original search, they supplemented all electronic searches with manual screening of trial registers and references contained in the included studies. Study selection, data extraction, and risk of bias assessments were performed inde­­pen­dently by two coders using standardized methods to ensure consistency and to eliminate potential errors. Findings from eight rct s involving 6,615 participants were pooled into meta-analyses to calculate the magnitude of effects that mobile text message reminders have on the rate of attendance at healthcare appointments compared to no reminders and phone call reminders.

Meta-analyses are regarded as powerful tools for deriving meaningful conclusions. However, there are situations in which it is neither reasonable nor appropriate to pool studies together using meta-analytic methods simply because there is extensive clinical heterogeneity between the included studies or variation in measurement tools, comparisons, or outcomes of interest. In these cases, systematic reviews can use qualitative synthesis methods such as vote counting, content analysis, classification schemes and tabulations, as an alternative approach to narratively synthesize the results of the independent studies included in the review. This form of review is known as qualitative systematic review.

A rigorous example of one such review in the eHealth domain is presented by Mickan, Atherton, Roberts, Heneghan, and Tilson (2014) on the use of handheld computers by healthcare professionals and their impact on access to information and clinical decision-making. In line with the methodological guide­lines for systematic reviews, these authors: (a) developed and registered with prospero ( www.crd.york.ac.uk/ prospero / ) an a priori review protocol; (b) conducted comprehensive searches for eligible studies using multiple databases and other supplementary strategies (e.g., forward searches); and (c) subsequently carried out study selection, data extraction, and risk of bias assessments in a duplicate manner to eliminate potential errors in the review process. Heterogeneity between the included studies in terms of reported outcomes and measures precluded the use of meta-analytic methods. To this end, the authors resorted to using narrative analysis and synthesis to describe the effectiveness of handheld computers on accessing information for clinical knowledge, adherence to safety and clinical quality guidelines, and diagnostic decision-making.

In recent years, the number of systematic reviews in the field of health informatics has increased considerably. Systematic reviews with discordant findings can cause great confusion and make it difficult for decision-makers to interpret the review-level evidence ( Moher, 2013 ). Therefore, there is a growing need for appraisal and synthesis of prior systematic reviews to ensure that decision-making is constantly informed by the best available accumulated evidence. Umbrella reviews , also known as overviews of systematic reviews, are tertiary types of evidence synthesis that aim to accomplish this; that is, they aim to compare and contrast findings from multiple systematic reviews and meta-analyses ( Becker & Oxman, 2008 ). Umbrella reviews generally adhere to the same principles and rigorous methodological guidelines used in systematic reviews. However, the unit of analysis in umbrella reviews is the systematic review rather than the primary study ( Becker & Oxman, 2008 ). Unlike systematic reviews that have a narrow focus of inquiry, umbrella reviews focus on broader research topics for which there are several potential interventions ( Smith, Devane, Begley, & Clarke, 2011 ). A recent umbrella review on the effects of home telemonitoring interventions for patients with heart failure critically appraised, compared, and synthesized evidence from 15 systematic reviews to investigate which types of home telemonitoring technologies and forms of interventions are more effective in reducing mortality and hospital admissions ( Kitsiou, Paré, & Jaana, 2015 ).

9.3.5. Realist Reviews

Realist reviews are theory-driven interpretative reviews developed to inform, enhance, or supplement conventional systematic reviews by making sense of heterogeneous evidence about complex interventions applied in diverse contexts in a way that informs policy decision-making ( Greenhalgh, Wong, Westhorp, & Pawson, 2011 ). They originated from criticisms of positivist systematic reviews which centre on their “simplistic” underlying assumptions ( Oates, 2011 ). As explained above, systematic reviews seek to identify causation. Such logic is appropriate for fields like medicine and education where findings of randomized controlled trials can be aggregated to see whether a new treatment or intervention does improve outcomes. However, many argue that it is not possible to establish such direct causal links between interventions and outcomes in fields such as social policy, management, and information systems where for any intervention there is unlikely to be a regular or consistent outcome ( Oates, 2011 ; Pawson, 2006 ; Rousseau, Manning, & Denyer, 2008 ).

To circumvent these limitations, Pawson, Greenhalgh, Harvey, and Walshe (2005) have proposed a new approach for synthesizing knowledge that seeks to unpack the mechanism of how “complex interventions” work in particular contexts. The basic research question — what works? — which is usually associated with systematic reviews changes to: what is it about this intervention that works, for whom, in what circumstances, in what respects and why? Realist reviews have no particular preference for either quantitative or qualitative evidence. As a theory-building approach, a realist review usually starts by articulating likely underlying mechanisms and then scrutinizes available evidence to find out whether and where these mechanisms are applicable ( Shepperd et al., 2009 ). Primary studies found in the extant literature are viewed as case studies which can test and modify the initial theories ( Rousseau et al., 2008 ).

The main objective pursued in the realist review conducted by Otte-Trojel, de Bont, Rundall, and van de Klundert (2014) was to examine how patient portals contribute to health service delivery and patient outcomes. The specific goals were to investigate how outcomes are produced and, most importantly, how variations in outcomes can be explained. The research team started with an exploratory review of background documents and research studies to identify ways in which patient portals may contribute to health service delivery and patient outcomes. The authors identified six main ways which represent “educated guesses” to be tested against the data in the evaluation studies. These studies were identified through a formal and systematic search in four databases between 2003 and 2013. Two members of the research team selected the articles using a pre-established list of inclusion and exclusion criteria and following a two-step procedure. The authors then extracted data from the selected articles and created several tables, one for each outcome category. They organized information to bring forward those mechanisms where patient portals contribute to outcomes and the variation in outcomes across different contexts.

9.3.6. Critical Reviews

Lastly, critical reviews aim to provide a critical evaluation and interpretive analysis of existing literature on a particular topic of interest to reveal strengths, weaknesses, contradictions, controversies, inconsistencies, and/or other important issues with respect to theories, hypotheses, research methods or results ( Baumeister & Leary, 1997 ; Kirkevold, 1997 ). Unlike other review types, critical reviews attempt to take a reflective account of the research that has been done in a particular area of interest, and assess its credibility by using appraisal instruments or critical interpretive methods. In this way, critical reviews attempt to constructively inform other scholars about the weaknesses of prior research and strengthen knowledge development by giving focus and direction to studies for further improvement ( Kirkevold, 1997 ).

Kitsiou, Paré, and Jaana (2013) provide an example of a critical review that assessed the methodological quality of prior systematic reviews of home telemonitoring studies for chronic patients. The authors conducted a comprehensive search on multiple databases to identify eligible reviews and subsequently used a validated instrument to conduct an in-depth quality appraisal. Results indicate that the majority of systematic reviews in this particular area suffer from important methodological flaws and biases that impair their internal validity and limit their usefulness for clinical and decision-making purposes. To this end, they provide a number of recommendations to strengthen knowledge development towards improving the design and execution of future reviews on home telemonitoring.

9.4. Summary

Table 9.1 outlines the main types of literature reviews that were described in the previous sub-sections and summarizes the main characteristics that distinguish one review type from another. It also includes key references to methodological guidelines and useful sources that can be used by eHealth scholars and researchers for planning and developing reviews.

Typology of Literature Reviews (adapted from Paré et al., 2015).

As shown in Table 9.1 , each review type addresses different kinds of research questions or objectives, which subsequently define and dictate the methods and approaches that need to be used to achieve the overarching goal(s) of the review. For example, in the case of narrative reviews, there is greater flexibility in searching and synthesizing articles ( Green et al., 2006 ). Researchers are often relatively free to use a diversity of approaches to search, identify, and select relevant scientific articles, describe their operational characteristics, present how the individual studies fit together, and formulate conclusions. On the other hand, systematic reviews are characterized by their high level of systematicity, rigour, and use of explicit methods, based on an “a priori” review plan that aims to minimize bias in the analysis and synthesis process (Higgins & Green, 2008). Some reviews are exploratory in nature (e.g., scoping/mapping reviews), whereas others may be conducted to discover patterns (e.g., descriptive reviews) or involve a synthesis approach that may include the critical analysis of prior research ( Paré et al., 2015 ). Hence, in order to select the most appropriate type of review, it is critical to know before embarking on a review project, why the research synthesis is conducted and what type of methods are best aligned with the pursued goals.

9.5. Concluding Remarks

In light of the increased use of evidence-based practice and research generating stronger evidence ( Grady et al., 2011 ; Lyden et al., 2013 ), review articles have become essential tools for summarizing, synthesizing, integrating or critically appraising prior knowledge in the eHealth field. As mentioned earlier, when rigorously conducted review articles represent powerful information sources for eHealth scholars and practitioners looking for state-of-the-art evidence. The typology of literature reviews we used herein will allow eHealth researchers, graduate students and practitioners to gain a better understanding of the similarities and differences between review types.

We must stress that this classification scheme does not privilege any specific type of review as being of higher quality than another ( Paré et al., 2015 ). As explained above, each type of review has its own strengths and limitations. Having said that, we realize that the methodological rigour of any review — be it qualitative, quantitative or mixed — is a critical aspect that should be considered seriously by prospective authors. In the present context, the notion of rigour refers to the reliability and validity of the review process described in section 9.2. For one thing, reliability is related to the reproducibility of the review process and steps, which is facilitated by a comprehensive documentation of the literature search process, extraction, coding and analysis performed in the review. Whether the search is comprehensive or not, whether it involves a methodical approach for data extraction and synthesis or not, it is important that the review documents in an explicit and transparent manner the steps and approach that were used in the process of its development. Next, validity characterizes the degree to which the review process was conducted appropriately. It goes beyond documentation and reflects decisions related to the selection of the sources, the search terms used, the period of time covered, the articles selected in the search, and the application of backward and forward searches ( vom Brocke et al., 2009 ). In short, the rigour of any review article is reflected by the explicitness of its methods (i.e., transparency) and the soundness of the approach used. We refer those interested in the concepts of rigour and quality to the work of Templier and Paré (2015) which offers a detailed set of methodological guidelines for conducting and evaluating various types of review articles.

To conclude, our main objective in this chapter was to demystify the various types of literature reviews that are central to the continuous development of the eHealth field. It is our hope that our descriptive account will serve as a valuable source for those conducting, evaluating or using reviews in this important and growing domain.

• Ammenwerth E., de Keizer N. An inventory of evaluation studies of information technology in health care. Trends in evaluation research, 1982-2002. International Journal of Medical Informatics. 2004; 44 (1):44–56. [ PubMed : 15778794 ]
• Anderson S., Allen P., Peckham S., Goodwin N. Asking the right questions: scoping studies in the commissioning of research on the organisation and delivery of health services. Health Research Policy and Systems. 2008; 6 (7):1–12. [ PMC free article : PMC2500008 ] [ PubMed : 18613961 ] [ CrossRef ]
• Archer N., Fevrier-Thomas U., Lokker C., McKibbon K. A., Straus S.E. Personal health records: a scoping review. Journal of American Medical Informatics Association. 2011; 18 (4):515–522. [ PMC free article : PMC3128401 ] [ PubMed : 21672914 ]
• Arksey H., O’Malley L. Scoping studies: towards a methodological framework. International Journal of Social Research Methodology. 2005; 8 (1):19–32.
• A systematic, tool-supported method for conducting literature reviews in information systems. Paper presented at the Proceedings of the 19th European Conference on Information Systems ( ecis 2011); June 9 to 11; Helsinki, Finland. 2011.
• Baumeister R. F., Leary M.R. Writing narrative literature reviews. Review of General Psychology. 1997; 1 (3):311–320.
• Becker L. A., Oxman A.D. In: Cochrane handbook for systematic reviews of interventions. Higgins J. P. T., Green S., editors. Hoboken, nj : John Wiley & Sons, Ltd; 2008. Overviews of reviews; pp. 607–631.
• Borenstein M., Hedges L., Higgins J., Rothstein H. Introduction to meta-analysis. Hoboken, nj : John Wiley & Sons Inc; 2009.
• Cook D. J., Mulrow C. D., Haynes B. Systematic reviews: Synthesis of best evidence for clinical decisions. Annals of Internal Medicine. 1997; 126 (5):376–380. [ PubMed : 9054282 ]
• Cooper H., Hedges L.V. In: The handbook of research synthesis and meta-analysis. 2nd ed. Cooper H., Hedges L. V., Valentine J. C., editors. New York: Russell Sage Foundation; 2009. Research synthesis as a scientific process; pp. 3–17.
• Cooper H. M. Organizing knowledge syntheses: A taxonomy of literature reviews. Knowledge in Society. 1988; 1 (1):104–126.
• Cronin P., Ryan F., Coughlan M. Undertaking a literature review: a step-by-step approach. British Journal of Nursing. 2008; 17 (1):38–43. [ PubMed : 18399395 ]
• Darlow S., Wen K.Y. Development testing of mobile health interventions for cancer patient self-management: A review. Health Informatics Journal. 2015 (online before print). [ PubMed : 25916831 ] [ CrossRef ]
• Daudt H. M., van Mossel C., Scott S.J. Enhancing the scoping study methodology: a large, inter-professional team’s experience with Arksey and O’Malley’s framework. bmc Medical Research Methodology. 2013; 13 :48. [ PMC free article : PMC3614526 ] [ PubMed : 23522333 ] [ CrossRef ]
• Davies P. The relevance of systematic reviews to educational policy and practice. Oxford Review of Education. 2000; 26 (3-4):365–378.
• Deeks J. J., Higgins J. P. T., Altman D.G. In: Cochrane handbook for systematic reviews of interventions. Higgins J. P. T., Green S., editors. Hoboken, nj : John Wiley & Sons, Ltd; 2008. Analysing data and undertaking meta-analyses; pp. 243–296.
• Deshazo J. P., Lavallie D. L., Wolf F.M. Publication trends in the medical informatics literature: 20 years of “Medical Informatics” in mesh . bmc Medical Informatics and Decision Making. 2009; 9 :7. [ PMC free article : PMC2652453 ] [ PubMed : 19159472 ] [ CrossRef ]
• Dixon-Woods M., Agarwal S., Jones D., Young B., Sutton A. Synthesising qualitative and quantitative evidence: a review of possible methods. Journal of Health Services Research and Policy. 2005; 10 (1):45–53. [ PubMed : 15667704 ]
• Finfgeld-Connett D., Johnson E.D. Literature search strategies for conducting knowledge-building and theory-generating qualitative systematic reviews. Journal of Advanced Nursing. 2013; 69 (1):194–204. [ PMC free article : PMC3424349 ] [ PubMed : 22591030 ]
• Grady B., Myers K. M., Nelson E. L., Belz N., Bennett L., Carnahan L. … Guidelines Working Group. Evidence-based practice for telemental health. Telemedicine Journal and E Health. 2011; 17 (2):131–148. [ PubMed : 21385026 ]
• Green B. N., Johnson C. D., Adams A. Writing narrative literature reviews for peer-reviewed journals: secrets of the trade. Journal of Chiropractic Medicine. 2006; 5 (3):101–117. [ PMC free article : PMC2647067 ] [ PubMed : 19674681 ]
• Greenhalgh T., Wong G., Westhorp G., Pawson R. Protocol–realist and meta-narrative evidence synthesis: evolving standards ( rameses ). bmc Medical Research Methodology. 2011; 11 :115. [ PMC free article : PMC3173389 ] [ PubMed : 21843376 ]
• Gurol-Urganci I., de Jongh T., Vodopivec-Jamsek V., Atun R., Car J. Mobile phone messaging reminders for attendance at healthcare appointments. Cochrane Database System Review. 2013; 12 cd 007458. [ PMC free article : PMC6485985 ] [ PubMed : 24310741 ] [ CrossRef ]
• Hart C. Doing a literature review: Releasing the social science research imagination. London: SAGE Publications; 1998.
• Higgins J. P. T., Green S., editors. Cochrane handbook for systematic reviews of interventions: Cochrane book series. Hoboken, nj : Wiley-Blackwell; 2008.
• Jesson J., Matheson L., Lacey F.M. Doing your literature review: traditional and systematic techniques. Los Angeles & London: SAGE Publications; 2011.
• King W. R., He J. Understanding the role and methods of meta-analysis in IS research. Communications of the Association for Information Systems. 2005; 16 :1.
• Kirkevold M. Integrative nursing research — an important strategy to further the development of nursing science and nursing practice. Journal of Advanced Nursing. 1997; 25 (5):977–984. [ PubMed : 9147203 ]
• Kitchenham B., Charters S. ebse Technical Report Version 2.3. Keele & Durham. uk : Keele University & University of Durham; 2007. Guidelines for performing systematic literature reviews in software engineering.
• Kitsiou S., Paré G., Jaana M. Systematic reviews and meta-analyses of home telemonitoring interventions for patients with chronic diseases: a critical assessment of their methodological quality. Journal of Medical Internet Research. 2013; 15 (7):e150. [ PMC free article : PMC3785977 ] [ PubMed : 23880072 ]
• Kitsiou S., Paré G., Jaana M. Effects of home telemonitoring interventions on patients with chronic heart failure: an overview of systematic reviews. Journal of Medical Internet Research. 2015; 17 (3):e63. [ PMC free article : PMC4376138 ] [ PubMed : 25768664 ]
• Levac D., Colquhoun H., O’Brien K. K. Scoping studies: advancing the methodology. Implementation Science. 2010; 5 (1):69. [ PMC free article : PMC2954944 ] [ PubMed : 20854677 ]
• Levy Y., Ellis T.J. A systems approach to conduct an effective literature review in support of information systems research. Informing Science. 2006; 9 :181–211.
• Liberati A., Altman D. G., Tetzlaff J., Mulrow C., Gøtzsche P. C., Ioannidis J. P. A. et al. Moher D. The prisma statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: Explanation and elaboration. Annals of Internal Medicine. 2009; 151 (4):W-65. [ PubMed : 19622512 ]
• Lyden J. R., Zickmund S. L., Bhargava T. D., Bryce C. L., Conroy M. B., Fischer G. S. et al. McTigue K. M. Implementing health information technology in a patient-centered manner: Patient experiences with an online evidence-based lifestyle intervention. Journal for Healthcare Quality. 2013; 35 (5):47–57. [ PubMed : 24004039 ]
• Mickan S., Atherton H., Roberts N. W., Heneghan C., Tilson J.K. Use of handheld computers in clinical practice: a systematic review. bmc Medical Informatics and Decision Making. 2014; 14 :56. [ PMC free article : PMC4099138 ] [ PubMed : 24998515 ]
• Moher D. The problem of duplicate systematic reviews. British Medical Journal. 2013; 347 (5040) [ PubMed : 23945367 ] [ CrossRef ]
• Montori V. M., Wilczynski N. L., Morgan D., Haynes R. B., Hedges T. Systematic reviews: a cross-sectional study of location and citation counts. bmc Medicine. 2003; 1 :2. [ PMC free article : PMC281591 ] [ PubMed : 14633274 ]
• Mulrow C. D. The medical review article: state of the science. Annals of Internal Medicine. 1987; 106 (3):485–488. [ PubMed : 3813259 ] [ CrossRef ]
• Evidence-based information systems: A decade later. Proceedings of the European Conference on Information Systems ; 2011. Retrieved from http://aisel ​.aisnet.org/cgi/viewcontent ​.cgi?article ​=1221&context ​=ecis2011 .
• Okoli C., Schabram K. A guide to conducting a systematic literature review of information systems research. ssrn Electronic Journal. 2010
• Otte-Trojel T., de Bont A., Rundall T. G., van de Klundert J. How outcomes are achieved through patient portals: a realist review. Journal of American Medical Informatics Association. 2014; 21 (4):751–757. [ PMC free article : PMC4078283 ] [ PubMed : 24503882 ]
• Paré G., Trudel M.-C., Jaana M., Kitsiou S. Synthesizing information systems knowledge: A typology of literature reviews. Information & Management. 2015; 52 (2):183–199.
• Patsopoulos N. A., Analatos A. A., Ioannidis J.P. A. Relative citation impact of various study designs in the health sciences. Journal of the American Medical Association. 2005; 293 (19):2362–2366. [ PubMed : 15900006 ]
• Paul M. M., Greene C. M., Newton-Dame R., Thorpe L. E., Perlman S. E., McVeigh K. H., Gourevitch M.N. The state of population health surveillance using electronic health records: A narrative review. Population Health Management. 2015; 18 (3):209–216. [ PubMed : 25608033 ]
• Pawson R. Evidence-based policy: a realist perspective. London: SAGE Publications; 2006.
• Pawson R., Greenhalgh T., Harvey G., Walshe K. Realist review—a new method of systematic review designed for complex policy interventions. Journal of Health Services Research & Policy. 2005; 10 (Suppl 1):21–34. [ PubMed : 16053581 ]
• Petersen K., Vakkalanka S., Kuzniarz L. Guidelines for conducting systematic mapping studies in software engineering: An update. Information and Software Technology. 2015; 64 :1–18.
• Petticrew M., Roberts H. Systematic reviews in the social sciences: A practical guide. Malden, ma : Blackwell Publishing Co; 2006.
• Rousseau D. M., Manning J., Denyer D. Evidence in management and organizational science: Assembling the field’s full weight of scientific knowledge through syntheses. The Academy of Management Annals. 2008; 2 (1):475–515.
• Rowe F. What literature review is not: diversity, boundaries and recommendations. European Journal of Information Systems. 2014; 23 (3):241–255.
• Shea B. J., Hamel C., Wells G. A., Bouter L. M., Kristjansson E., Grimshaw J. et al. Boers M. amstar is a reliable and valid measurement tool to assess the methodological quality of systematic reviews. Journal of Clinical Epidemiology. 2009; 62 (10):1013–1020. [ PubMed : 19230606 ]
• Shepperd S., Lewin S., Straus S., Clarke M., Eccles M. P., Fitzpatrick R. et al. Sheikh A. Can we systematically review studies that evaluate complex interventions? PLoS Medicine. 2009; 6 (8):e1000086. [ PMC free article : PMC2717209 ] [ PubMed : 19668360 ]
• Silva B. M., Rodrigues J. J., de la Torre Díez I., López-Coronado M., Saleem K. Mobile-health: A review of current state in 2015. Journal of Biomedical Informatics. 2015; 56 :265–272. [ PubMed : 26071682 ]
• Smith V., Devane D., Begley C., Clarke M. Methodology in conducting a systematic review of systematic reviews of healthcare interventions. bmc Medical Research Methodology. 2011; 11 (1):15. [ PMC free article : PMC3039637 ] [ PubMed : 21291558 ]
• Sylvester A., Tate M., Johnstone D. Beyond synthesis: re-presenting heterogeneous research literature. Behaviour & Information Technology. 2013; 32 (12):1199–1215.
• Templier M., Paré G. A framework for guiding and evaluating literature reviews. Communications of the Association for Information Systems. 2015; 37 (6):112–137.
• Thomas J., Harden A. Methods for the thematic synthesis of qualitative research in systematic reviews. bmc Medical Research Methodology. 2008; 8 (1):45. [ PMC free article : PMC2478656 ] [ PubMed : 18616818 ]
• Reconstructing the giant: on the importance of rigour in documenting the literature search process. Paper presented at the Proceedings of the 17th European Conference on Information Systems ( ecis 2009); Verona, Italy. 2009.
• Webster J., Watson R.T. Analyzing the past to prepare for the future: Writing a literature review. Management Information Systems Quarterly. 2002; 26 (2):11.
• Whitlock E. P., Lin J. S., Chou R., Shekelle P., Robinson K.A. Using existing systematic reviews in complex systematic reviews. Annals of Internal Medicine. 2008; 148 (10):776–782. [ PubMed : 18490690 ]

This publication is licensed under a Creative Commons License, Attribution-Noncommercial 4.0 International License (CC BY-NC 4.0): see https://creativecommons.org/licenses/by-nc/4.0/

• Cite this Page Paré G, Kitsiou S. Chapter 9 Methods for Literature Reviews. In: Lau F, Kuziemsky C, editors. Handbook of eHealth Evaluation: An Evidence-based Approach [Internet]. Victoria (BC): University of Victoria; 2017 Feb 27.
• PDF version of this title (4.5M)

In this Page

• Introduction
• Overview of the Literature Review Process and Steps
• Types of Review Articles and Brief Illustrations
• Concluding Remarks

Related information

• PMC PubMed Central citations
• PubMed Links to PubMed

Recent Activity

• Chapter 9 Methods for Literature Reviews - Handbook of eHealth Evaluation: An Ev... Chapter 9 Methods for Literature Reviews - Handbook of eHealth Evaluation: An Evidence-based Approach

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

Connect with NLM

National Library of Medicine 8600 Rockville Pike Bethesda, MD 20894

Web Policies FOIA HHS Vulnerability Disclosure

Help Accessibility Careers

A review of radioactive waste processing and disposal from a life cycle environmental perspective

• Open access
• Published: 18 September 2024

Cite this article

You have full access to this open access article

• Rachael Clayton 1 ,
• Joel Kirk 1 ,
• Anthony Banford 2 &
• Laurence Stamford 1  

The role of nuclear power in a more sustainable, ‘net zero’ energy sector is an important focal point of research. Given the large volume of existing legacy wastes and the future waste arisings that nuclear expansion would entail, attention is needed in the ‘back-end’ of the nuclear fuel cycle: processing (including treatment and conditioning) and disposal of radioactive waste. The range of waste processing techniques already in operation is broad and complex, and many novel technologies are under development. However, whilst prior work only focused on technology development and direct emissions, particularly in post-processing and disposal, a life cycle perspective is underutilised. This review analyses the landscape of life cycle assessment (LCA) within the nuclear sector, focusing on radioactive waste management, decommissioning and disposal. A literature search yielded 225 journal articles plus additional grey literature, yet only eight relevant LCAs were identified. Most studies identified adopted power generation as a functional unit and focused on nuclear power plants currently in operation. The major research gap identified in this review is the lack of holistic life cycle thinking surrounding radioactive waste management caused by poor granularity of published data related to waste treatment, conditioning and disposal, making strategic analysis challenging from the perspective of sustainability. Future LCA work should focus on technologies and processes in the back-end nuclear fuel cycle with considerable granularity to allow system ‘hotspots’ to be identified and strategic research and policy decisions to be taken. Efforts should also be made to incorporate recent developments in radiological impact assessment methodologies such as UCrad.

Graphical abstract

Relevant life cycle assessment literature for the back end of the nuclear fuel cycle and the lack of data on waste processing technologies

Avoid common mistakes on your manuscript.

Introduction

Decommissioning involves the dismantling and demolition of nuclear facilities and removal and/or reduction of radioactive hazards from a nuclear site. A huge range of radioactive materials may be present once a facility has ceased operation, most of which can be categorised as high-, intermediate-, low- and very low-level waste: HLW, ILW, LLW and VLLW, respectively. At the high activity end of the spectrum, HLW incurs significant temperature rises due to its radioactivity, which must be factored into the design of storage and disposal facilities (NDA 2024 ). This may include spent nuclear fuel (SF), depending on national policy. At the other end of the spectrum, for example, LLW has radioactive content not exceeding 4 Giga-becquerels per tonne of alpha activity or 12 Giga-becquerels per tonne of beta/gamma activity. (NDA 2017) including materials like topsoil from the site. The VLLW category includes any waste of low enough activity that it is suitable for disposal through municipal routes. In most countries, the owner or operator of the nuclear facility is responsible for the safe decommissioning of a plant once it ceases to operate, with most operators having to prove before the plant is commissioned that there is a financial plan in place to cover the cost of decommissioning (World Nuclear Association 2021 ).

Once the active/contaminated material is removed from an NPP it usually needs to be processed to immobilise any radionuclides that could migrate during long-term storage and to reduce the volume of material where possible before its final disposal. Many countries generating radioactive waste agree that final disposal should either take the form of a deep geological disposal facility (GDF), ranging from hundreds to thousands of metres below ground level, or a near-surface disposal facility, only tens of metres below ground level. Of the countries planning a GDF, Finland is at the most advanced stage: An operator for its spent nuclear fuel repository at Onkalo has recently applied for an operating license (Posiva 2021 ), and the Finnish government have published a national programme on the management of spent nuclear fuel and radioactive waste (Ministry of Economic Affairs and Employment 2022a ). In the USA, there have been ongoing talks about the Yucca Mountain geological disposal facility in Nevada being open for used fuel but with public objection being so high, this is likely not to come to fruition (US EPA 2022). However, it is important to note that a GDF is essential for the safe storage of heat-generating HLW regardless of whether or not reprocessing is conducted.

Different countries’ historical strategies have influenced their preparedness for final disposal, with Finland having not reprocessed spent fuel meaning their waste forms are fewer and the processing options well known (Ministry of Economic Affairs and Employment 2022b ). In contrast, countries that have reprocessed used fuel, particularly those with multiple generations of nuclear power plants, have reduced the direct fuel disposal burden but are left with more varied radioactive waste forms and larger volumes of ILW/LLW, with differing processing requirements before final disposal. There are proven benefits to both a closed an open fuel cycle from an energy generation standpoint—where, in a closed fuel cycle, there is scope for the recovery of spent fuel for further enrichment or conversion into mixed oxide (MOX) fuel. All waste processing and disposal decisions have potentially significant environmental and economic impacts and so must be considered carefully.

In addition to existing waste, new waste production rates might increase over the coming decades as decarbonisation policies lead to growth in nuclear power deployment. For instance, the IEA’s Net Zero Scenario suggests a tripling of nuclear power capacity by 2030 followed by further increases to 2040 (IEA 2022 ). Although there is much activity within the nuclear sector towards this target, at current pace, it is unlikely that such a capacity increase will be achievable due to the long construction timeframe for NPPs. Nevertheless, whilst waste produced per unit of electricity generated is expected to decrease as older reactor designs are replaced, the overall increase in installed capacity will inevitably lead to new waste production in the coming decades as well as the continual generation of waste during the operational phase of existing reactors. Resultantly, an upsurge in reactor decommissioning is inevitable as new reactor designs such as GEN IV and SMRs replace the current active fleets. With these decommissioning activities come an enormous amount of waste which must be processed and disposed of using processes that are potentially material- and energy-intensive. In this context, and with a growing global emphasis on environmental stewardship and sustainability (OECD 2022 ), it is imperative that the impacts of nuclear decommissioning on the environment are at the forefront of discussions, including when looking to develop and adopt new techniques, all of which will come with varying degrees of environmental and social impact.

In line with the increasing emphasis on environmental sustainability, there is increasing interest in following the waste hierarchy and its associated circular economy principles. This encourages reuse and recycling of waste materials as opposed to disposal and is highly applicable to the nuclear industry (for instance in the decontamination and use/recycling of surface-contaminated metals). Such approaches are in need of examination throughout the back-end of the fuel cycle and may themselves incur sustainability impacts from additional processing steps which will necessitate impact minimisation and the balancing of benefits against detriment in a holistic manner.

Therefore, it is important that relevant studies such as life cycle assessment (LCA) are undertaken to aid decision-making and technology development based on holistic, cradle-to-grave information. This paper will analyse the current landscape of nuclear waste processing technologies and the existing LCA focusing on back-end nuclear processes.

European nuclear waste inventory

As shown in Table  1 , the volume of radioactive waste in storage across the EU as of 2016 is 983,000 m 3 (this volume includes the UK inventory). The volume of radioactive waste disposed of in 3 years from 2013 to 2016 was 167,000 m 3 , and this is expected to increase through to 2030 as more reactors come offline, as shown in Table  2 . It is important to note that these forecasts end in 2030, but further wastes will arise for decades, leading to much higher volumes than those shown in the tables: for instance, future arisings of VLLW—a sub-category of LLW comprised of waste that can be safely disposed of with municipal, commercial, or industrial waste, or can be disposed of in specified landfill—in the UK alone are estimated at 2,750,000 m 3 (Nuclear Decommissioning Authority 2023 ). The majority of this waste, especially LLW, ILW and HLW, will need to be treated before final disposal to produce a more stable waste form. These large waste volumes across Europe necessitate a focus on the back-end nuclear fuel cycle from an environmental sustainability perspective.

Nuclear fuel cycle back-end

As shown in Fig.  1 , the nuclear fuel cycle can be split into two sections, the front-end and back-end, with the power generation acting as a ‘dividing line’ between the two (Choppin et al., 2013 ). Front-end operations generally include mining, refining, enrichment, fuel fabrication and any other activities leading up to fuel irradiation within the power plant. Back-end processes are considered as any activities that occur post fuel irradiation which include interim storage, reprocessing (when concerning a closed fuel cycle), waste processing, storage and final disposal.

The nuclear fuel cycle (adapted from (IAEA 2011 ))

Initially, radioactive waste is stored in an interim storage facility either to decay in radioactivity or until a final disposal route is available. Some wastes are stored until they naturally decay to limits low enough for disposal via lower activity waste routes.

Waste processing covers all activities undertaken to make waste suitable for disposal. This contains waste treatment steps such as compaction, incineration and other state transformative activities. It also includes conditioning—the consolidation of the treated waste into a solid form ready for disposal, i.e. through encapsulation in cement or via vitrification. Once conditioned, the waste is then further stored awaiting final disposal.

In the case of a closed nuclear cycle, the SF is not processed for disposal; it is reprocessed. After re-enriching or conversion to MOX fuel, it can be reintroduced into Gen III/III + reactors where 25–30% more energy can be released from the original radioactive material (IAEA, 2020). In the case of fast reactors, this increase in energy yield is much higher. If the used fuel is not to be reprocessed or can no longer be reprocessed, it will then be immobilised for disposal.

The waste processing techniques throughout the above stages vary greatly based on wasteform, radioactivity and location. Various techniques are currently in use or under development, as outlined by the examples in Table  3 .

Most countries with radioactive waste are considering deep geological and/or near-surface disposal facilities for the final disposal of waste with different levels of maturity of implementation. Repositories already exist in many countries at ground level such as the low-level waste repository (LLWR) in the UK and below ground level at facilities such as the SFR final repository in Sweden for short-lived radioactive waste (SKB 2021 ). Deep geological disposal is the official policy for the disposal of ILW and HLW in multiple countries (but note that SF is not considered a waste in all countries). The design of each repository is dependent on the geology of the surrounding area, and Finland’s Onkalo repository is the most advanced design, set to be operational in the mid-2020s. Onkalo will be the first repository licensed for the disposal of SF (Vira 2017 ) (Fig.  2 ).

Life cycle assessment framework according to ISO 14040 (adapted from (ISO 2006a ))

Life cycle assessment (LCA) is ‘an environmental management tool that helps to translate life cycle thinking into a quantitative measure of environmental sustainability of products, processes or activities on a life cycle basis’ (Azapagic et al. 2011 ). LCA is useful for finding the overall environmental impact of a product/process and can identify emission ‘hotspots’ so targeted emission reduction strategies can be implemented. LCA can also be used to compare products/process in advance of their application driving reduction in both emission and overall cost. According to the international organisation for standardisation (ISO) standard 14,040/14044, life cycle assessment should follow four steps:

Goal and scope analysis

In this step, it is decided how much of the product/process life cycle will be assessed and what the goal of the study will be, whether that be discovery of overall environmental impact, or investigation of emission ‘hotspots’ (process areas of significant environmental impact). The system boundaries are defined, such as cradle-to-grave, encompassing the whole life cycle or a smaller boundary such as cradle-to-gate, gate-to-grave, etc. If this is more suitable for the process being studied. Functional units (FU) are defined as the unit of assessment, and the limitations and assumptions are described.

Inventory analysis

Inventory analysis describes the material and energy flows within the system, where environmental burdens of the activity under study are identified and quantified. This includes procuring data from reliable sources so that the outputs of the LCA study can be trusted.

Impact assessment (LCIA)

In this stage, the environmental burdens are converted into environmental impacts, classified into themes such as climate change, loss of biodiversity, human toxicity, etc., depending on the goal of the study. Commonly used LCIA methodologies include CML (Guinée and Lindeijer 2002 ), ReCiPe (Goedkoop et al. 2009 ), Eco-indicator 99 (Goedkeep and Spriensma 2001 ) and Impact 2002 + (Jolliet et al. 2003 ). According to a survey (iPoint 2018 ), the majority of practitioners use the ReCiPe methodology. Some nuclear LCA studies have also included radiological impact assessments of nuclear energy generation, though no standardised methodology currently exists.

Interpretation

The final stage involves analysis of the resulting impact categories, including identification of hotspots, sensitivity analysis and selection of the best scenarios/alternatives.

The sources selected were Scopus, Google Scholar and The University of Manchester (UoM) library. Scopus was selected as an internationally-acclaimed source of peer-reviewed publications with an independent Content Selection & Advisory Board comprised of leaders in their respective fields. Google Scholar was selected as a broader search engine to gather more niche literature sources including those not published in scientific journals (grey literature). The University of Manchester library was selected as a supplement to gather local research including reports and PhD theses. A specific date field of 2010–2022 was applied on the Google Scholar and Scopus searches (unavailable with UoM) to encompass the decade prior to the commencement of the EU PREDIS project. Due to the very limited number of relevant articles despite the increased application of LCA in recent years, the authors deemed it extremely unlikely that relevant articles would be found prior to 2010.

The key words selected for each of the source searches included common terms and term groupings such as ‘radioactive waste/nuclear waste’, ‘back-end’, ‘liquid’ and ‘solid’ with optional terms including ‘organic’ also being included. Synonyms which are prevalent within the nuclear industry such as ‘decommissioning’ and ‘end of life’ were also considered. Due to the differing functionality of certain search engines, specific strings of search terms had to be formulated differently in order to yield appropriate results, as indicated in Fig.  3 .

Results from the literature review

The specific search parameters used for this review are shown in Fig.  3 , alongside the number of results yielded. Searches were conducted in February and September 2022.

Following the initial search (see Fig.  3 ), the results were screened for relevance using the following main criteria:

Specific mention of radioactive/nuclear waste processing technologies

Specific mention of liquid and/or solid radioactive/nuclear waste

Any mention of life cycle assessment or life cycle costing

A specific criterion was made for papers of partial relevance which provided useful insight into the fundamental understanding of the review topic or mentioned technology which has not yet been implemented, e.g. those for use on GEN IV reactors (Koltun et al. 2018 ).

The literature which was of no relevance was simply rejected from the review if none of the criteria above were satisfied. This is notable in the search results shown in Fig.  3 , ‘(life AND cycle AND assessment) AND (solid AND radioactive AND waste)’, where 12 search results were produced but none were of relevance to the literature review as they focused on non-nuclear technologies.

Many extensive life cycle assessments of nuclear power exist but were not explicit about their coverage of waste processing, or used data that lacked an explicit description of the waste processing or disposal route being considered (Warner and Heath 2012 ; Nian et al. 2014 , Lenzen, 2008 ).

Of the 225 search results screened after identification through Scopus, Google Scholar and UoM library (see Fig.  2 ), 31.69% were relevant to this study of nuclear LCA. The yield of results was as predicted, with few making it past the screening process due to lack of relevance. The Scopus library of published literature proved to be the most effective and Google Scholar to be the least effective based on the proportion of relevant publications. The University of Manchester digital library yielded only a single relevant paper, which was also found via the other literary sources.

Due to the limited volume of literature available in this field, grey literature was also screened separately. This included reports by the International Atomic Energy Agency (IAEA) and other government agencies which detailed nuclear ‘back-end’ processes including waste processing and final disposal alongside discussion of guidelines and policy, but due to the lack of inclusion of LCA methodology within these reports, they did not meet the established criteria and, therefore, did not pass the screening process.

For the relevant literature, the process of ‘snowballing’ was also applied by reviewing the literature cited by each study to identify any remaining items of relevance.

Results and discussion

The purpose of this section is to analyse the existing literature regarding both liquid and solid nuclear waste within the scope of LCA. The discussion below is structured to address the key elements of LCA as defined in the ISO 14040–44 standards (ISO 2006a ), namely the overall goal and scope, the system boundaries, functional unit, inventory data sources, impact assessment methods and results.

Overall, it is clear from the literature search process that the majority of nuclear-related LCA studies have used the entire fuel cycle as their system boundary, in which the granularity of back-end processes is minimal; often the entire back-end is represented as simply decommissioning followed by disposal, with little commentary or detail provided within these steps.

Consequently, LCA data related specifically to the back-end of the fuel cycle is limited. This section will review the information available to conduct a gap analysis and ultimately inform the direction of future data gathering.

Table 4 shows the final selection of screened studies applying LCA principles to the nuclear back-end, demonstrating the limited number of studies in the literature.

Alongside this lack of data, some may become outdated as policy changes are made. For example, an in-depth LCA study of the effects of decommissioning the Magnox reactor fleet across the UK (Wallbridge et al. 2013 ) is already out of date due to strategy changes affecting the decommissioning timeline: Though the new strategy appreciates the benefits of deferred decommissioning, ‘it is not appropriate as a blanket strategy for all reactors in the Magnox fleet’ and ‘for some sites this will result in their decommissioning being brought forward’ (Nuclear Decommissioning Authority 2021 ). Such changes to decommissioning timelines have consequences on material usage, background energy mix and disposal route options applied to the processes undertaken, and therefore on the overall environmental impact.

The scarcity of back-end fuel cycle LCA information appears to be caused by two predominant drivers: firstly, much prior LCA work in the energy sector has focused on comparison to other energy generation techniques, leading to a focus on the generation process and oversimplification of the disposal process where waste processing is missed, e.g. (Gagnon et al. 2002 ; Santoyo-Castelazo et al. 2011 ; Siddiqui and Dincer 2017 ), particularly affecting nuclear power due to the complexity and variety of its waste processing requirements. Secondly, there is often a lack of clarity over the exact processes associated with power plant end-of-life and used fuel processing, in some cases accentuated by a lack of back-end fuel cycle policies in the country under assessment (Lee et al. 2000 ; Turconi et al. 2013 ).

Another possible reason for the lack of attention paid to the back-end is the apparent dominance of front-end activities in environmental impacts: When the entire nuclear life cycle is considered, existing studies suggest that the front-end processes (mining, separating and purifying) account for > 70% of the overall environmental footprint, in part because most of those processes have remained similar since their development in the 1950s–1960s (Poinssot et al. 2016 ). Similar conclusions, i.e. that the front-end is the major contributor to the emissions associated with nuclear power generation, have been reached by other LCAs (Lenzen 2008 ; Warner and Heath 2012 ) Whilst this front-end dominance may be the case, improved granularity of data on the back-end processes would help to verify this claim and may well offer help to identify opportunities to minimise waste and reduce overall environmental impacts. This uncertainty is further accentuated by the huge variation in GHG emission factors in nuclear LCA studies ‘up to one order of magnitude’, although this is largely attributable to whether a study included uranium enrichment in the life cycle, and to a lesser extent the methodology and technological approaches considered (Turconi et al. 2013 ).

The limited research in this area suggests that solid wastes may be responsible for a greater environmental impact than liquid wastes due to the latter’s lesser volumes as can be seen in the results presented by Wallbridge et al. ( 2013 ) where liquid wastes (sludges and effluent) produced in the decommissioning of an NPP made up 6 waste packages whereas the solid contaminated waste required > 6970 packages. (In this study, ‘packages’ were simplified for LLW to 2.2 t steel and a ratio of 2:1 of waste to grout, and for ILW 4.2 t steel and a ratio of 1:1 of waste to grout. These values were averages across multiple waste package types.) The smaller number of packages for liquid waste is due to liquid effluents predominantly being treated, yielding further solid waste, and discharged whilst solids are more likely to be stored during the operational phase. It is typical for solid wastes to be concrete, steel and other contaminated materials from decommissioning activities which are comparatively more massive. However, the greater prevalence of solid waste generation within decommissioning activities means that, over the life of a plant, their production rates vary more than those of liquids, which typically come from analysis and maintenance. These differences should be taken into consideration when considering the granularity of LCA modelling.

Goal definitions

The goals of each LCA study identified in this review (Table  4 ) were either related to the whole life cycle of NPPs, back-end waste processing technologies or reactor site decommissioning. From all the papers reviewed, most gave a clear goal and scope outline within the first few subsections whilst one did not (Pomponi and Hart 2021 ) (though it could be ascertained through context) whilst others compared pre-existing LCA studies, and therefore, the goal and scope for each were not described (Fthenakis and Kim 2007 ). The paper by (Guidi et al. 2010 ) is the only LCA study whose goal does not consider large-scale NPP processes but instead focuses on a specific waste form’s treatment and aims to quantify the impacts of decontaminating a surface using a novel technology in comparison with an existing approach.

System boundaries

System boundaries were well defined in all papers. The study by Wallbridge et al. ( 2013 ) offers the most comprehensive look at applicable system boundaries for this review. It encompassed the stages of decommissioning—including the waste arising from decommissioning activities, temporary storage and final disposal of nuclear waste.

Pomponi and Hart ( 2021 ) acknowledge the omission of decommissioning activities in existing literature prior to their assessment of a European PWR, a notable case study being Ding et al. ( 2017 ) with the decommissioning phase being absent in their assessment of energy infrastructure in China, but still encompasing back-end processes within the system boundaries.

Fthenakis and Kim ( 2007 ) also mentions the ‘outdated information’ within LCA databases for waste processing activities and decommissioning stages, leading to a lack of any specific analysis within their assessment. Godsey (2019) also references the lack of back-end data available, attempting to draw additional information in their assessment of SMRs in the US nuclear fuel cycle from other sites, specifically the VVER facility in Lubin, Germany, noting the limitations of this comparison. The authors note that, of all papers in this review, only one (Guidi et al. 2010 ) focused on the environmental impacts of a specific waste treatment method: the treatment of contaminated surfaces through the use of strippable coatings and vacuum technology.

There is an inherent uncertainty in developing accurate models related to decommissioning as a result of the potentially large timescales involved with resultant differing energy mixes and disposal routes, as well as the policy changes that may arise; this is acknowledged by Paulillo et al. ( 2021 ) and Koltun et al. ( 2018 ) within their assessments. Paulillo et al. do specifically reference the waste generated through reprocessing scenarios (i.e. via THORP), but a granular assessment of waste management and plant decommissioning is outside of its scope. This is also true of Lee et al. ( 2000 ) which focus more so on spent nuclear fuel in the case of the Korean once-through cycle.

There is a general focus on the system boundaries being the whole reactor site including during the operational/power generation period without a great deal of consideration for the back-end of the nuclear fuel cycle. However, in recent years, there has been an increase in the consideration of decommissioning projects, i.e. the Magnox fleet in the UK (Wallbridge et al. 2013 ) which include the disposal of various types of radioactive wastes. With further expansion of the system boundaries to include waste processing and disposal methods, insight could be gained as to the impacts of these processes as waste volumes and therefore processing requirments will increase.

Functional units

A functional unit (FU) is used as a ‘quantified description of the function of a product [or system] that serves as the reference basis for all calculations regarding impact assessment’ (Arzoumanidis et al. 2020 ). Of the limited number of LCA studies on nuclear energy generation/decommissioning, the majority use the entire life cycle of a NPP, or a unit of electricity generated within this life cycle. For instance, Koltun et al. ( 2018 ) selected 1 MWhe of generation as the FU when assessing the potential impacts of GEN IV plants, and similarly, (Lee et al. 2000 ) chose a FU of 1 GWh electricity delivered to consumers. Only one paper considers specifically a waste treatment process (Guidi et al. 2010 ).

In Wallbridge et al. ( 2013 ), the functional unit was the ‘decommissioning of one Magnox power plant’. This is unique among the identified papers and aligns with the fact that this was the only paper focused on the decommissioning of a single NPP. Even in this case, the global warming potential was also expressed per kWh generated in order to contextualise against other studies such as those above.

Life cycle inventory (LCI) data sources

Almost all papers provided detail on their data sources, with data on the foreground system primarily arising directly from power plant operators or from material published by plant operators. Background data were typically sourced from the database Ecoinvent. However, some papers provided less detail, such as Koltun et al. ( 2018 ) which only specifies the source of their background data as ‘Australian conditions’.

The Ecoinvent database, upon which these studies rely, has little data directly related to back-end processes and most is Swiss-centric due to the database’s origins in Zurich, Switzerland. For example, the data on the environmental impacts of the construction of a geological disposal facility for nuclear waste are based on a Swiss design; therefore, if it is used in an LCA study, it must be edited to reflect other countries’ GDF designs, as no two are the same due to differences in host rock, depth, engineering approaches, etc. In some cases, as seen in Wallbridge et al. ( 2013 ), the disposal facility model is simplified and condensed to contain only its steel and concrete components, reducing the likelihood of error but simultaneously risking an underestimation of the true impacts.

There may also be data specificity and age implications from the use of Ecoinvent by the majority of LCA practitioners. For example, most data for countries other than Switzerland are modified datasets based on original Swiss data as opposed to being built from the ground up. The problem of data being outdated is especially prominent in nuclear processes: for instance, the data on electricity generation from boiling water reactors originate from the period 1990–2015; similarly, the process of constructing a nuclear fuel factory has not been updated since 2000, and the data for the construction of a nuclear waste repository have not been updated since 2002 (Ecoinvent 2023 ). This does not mean that Ecoinvent should be avoided—on the contrary, it has the most complete datasets available—but it does highlight the lack of alternative nuclear sector datasets for LCA practitioners due to insufficient work in this area. Therefore, these existing datasets must be carefully assessed prior to use to ensure their validity in a modern model. Ecoinvent is transparent and provides comprehensive documentation on the source of data, and this should be evaluated to ensure that inappropriate data and assumptions are not implicit across multiple LCA models throughout the literature.

Software and impact assessment methodologies

Of the LCA studies reviewed only four discussed their impact assessment methodology: CML2001 (Wallbridge et al. 2013 ), Eco-indicator 99 (Guidi et al. 2010 ), ReCiPe (Godsey 2019 ) and UCrad (Paulillo et al. 2021 ). Other literature identified by this review, which did not pass the screening process due to a lack of LCA within the nuclear context, also applied the CML (Guinée and Lindeijer 2002 ) and ReCiPe (Goedkoop et al. 2009 ) methodologies most frequently. The study conducted by (Godsey 2019 ) addressing the US nuclear fuel cycle provides significant discussion and justification around their choice to use the older ReCiPe 2008 method as opposed to ReCiPe 2016 due to validity uncertainties in their software.

Whilst ISO 14040 and 14,044 do not require justification of the selection of an impact assessment methodology, they do specify that it should be clearly reported, and that the choice of metrics should align with the goal and scope of the study (ISO 2006a , ISO 2006b ). Consequently, of the studies reviewed here, the only ones compliant with the ISO are Wallbridge et al. ( 2013 ), Godsey ( 2019 ), Guidi et al. ( 2010 ) and Paulillo et al. ( 2020 ).

So far, radiological impacts have only been considered in nuclear LCA studies to a relatively basic standard due to the simplicity of existing LCA impact assessment models for radiological discharges. Recently, a paper was published by Paulillo et al. ( 2020 ) comparing two methodologies for quantifying ionising radiation impacts: UCrad and critical group methodology (CGM). These were compared to a pre-existing approach used in LCIA called Human Health Damage (HHD) (Frischknecht et al. 2000 ) which has been described as ‘recommended but in need of some improvements’ (Hauschild et al. 2013 ). Other radiological impact methodologies proposed exclusively for LCA applications have been reviewed but were not considered sufficiently comprehensive (Paulillo et al. 2020 ). The outcome of the review was that ‘characterisation factors from the CGM methodology are strongly affected by radioactive decay at low half-life and by dilution at large distances. Conversely, UCrad factors are not affected by dilution and are affected less than CGM by radioactive decay’. Therefore, UCrad is more appropriate than CGM for LCA as it is consistent with the general approach used in LCIA. There is a prescribed necessity for the further exploration of radiological assessment methodologies which could be applied to nuclear-related LCA, both back-end and otherwise. For instance, approaches included in the most common life cycle impact assessment methodologies are based on absorbed dose or exposure relative to reference isotopes such as Co-60 (Huijbregts et al. 2016 ) and U-235 (European Platform on LCA 2022 ), whilst non-LCA studies have considered other metrics such as collective dose (person-Sieverts) over a million years and Tier 1 ERICA score (Abrahamsen-Mills et al. 2021 ).

Although not an LCA study, Poinssot et al. ( 2016 ) discussed the opportunities available to decrease the environmental footprint of nuclear energy generation using similar indicators such as GHG emissions, atmospheric pollution (a quantification of the combined mass of SOx and NOx released per GW electrical power), land use, water consumption/withdrawal and the production of technological waste. Similarly, Sheldon et al. ( 2015 ) described the impact of the long-term storage of radioactive waste and impact of a catastrophic event which they have defined as the probability of total failure multiplied by the replacement energy costs.

The choice of impact assessment methodology can have a great influence on the reported impacts. As the ISO standard does not provide recommendations on the method which should be used, many organisations and governmental bodies have compared and evaluated different methodologies and provide their own recommendations for the best available approach as outlined by (Rosenbaum et al. 2018 ). The European Commission recommends the use of ILCD (EC-JRC 2011 ) and Environmental Footprint (EF) (European Commission 2021 ), the US Government recommends TRACI, though it has noted in best practice guidance that this LCIA methodology has not been updated since 2021 and, therefore, has ‘recommended to utilize the IPCC AR6 GWP characterization factors for translation of GHG emissions to Global Warming Potential impacts as a replacement for the factors in TRACI’ (U.S. DOE 2022 ). There does not exist a recommended LCIA methodology within the UK or wider nuclear industry. LCA of nuclear processes might benefit from the adoption of an LCIA methodology to assist in the comparison of results as it would allow assessments from multiple sources to be comparable between each other, aiding in decision-making at both an application level and policy making level.

LCA results

Due to the variety of system boundaries within the LCAs screened, the direct comparison of their results is difficult, although many share similar conclusions.

Firstly, the mining/milling of virgin resources such as uranium from open-pit mines appears to be a prevailing factor in several studies. For instance, when assessing the viability of SMRs, Godsey ( 2019 ) found that the LCA had a strong dependence on the boundary conditions applied and when incorporating the front-end, the mining practices utilised were an area of particular sensitivity, narrowed down to the source of the energy used for these processes. This resulted in recommendations that were also reflected in an LCA conducted by (Lee et al. 2000 ), who recommend that mining practices should be considered due to their dominant impacts.

Parallel to the above, (Fthenakis and Kim 2007 ) found that in their LCA based on the nuclear fuel cycle in the USA, front-end practices were also dominant citing the diffusion enrichment of nuclear fuel as the most prominent factor contributing ~ 50% of total GWP in their baseline scenario with limited impacts from sensitivity analysis.

The recycling of spent nuclear fuel to prevent the mining of virgin material was discussed in an LCA by Paulillo et al. ( 2021 ) which looked at reprocessing scenarios in the UK and argued that it was essential for policy makers to consider the reimplementation of reprocessing of SF to reduce environmental impacts.

When directly considering the back-end of the nuclear fuel cycle, Wallbridge et al. ( 2013 ) highlighted the impacts of the decommissioning of the Trawsfynydd site showcasing the dominance of the deconstruction, disposal and temporary storage—mirrored by Guidi et al. ( 2010 )—which were notable hotspots. The conclusion of the LCA, based on the identification of the model’s sensitivity to energy mix, was to suggest that a period of quiescence could be considered to allow for the national grid to decarbonise. As described in Table  4 , all other studies screened also considered varying aspects of the back-end of the nuclear fuel cycle but with limited data resolution, i.e. taking a top level view of back-end processes as opposed to individual waste processing/disposal pathways. For example, within their LCA of the entire SMR life cycle, Godsey ( 2019 ) simplified ‘waste management’ to comprise only the steel and cement required for the conditioning of waste rather than individual waste processing pathways for different waste types and their associated energy requirements. This lack of granularity means that accurate assessment of the impacts/comparison between studies of individual back-end processes is not possible.

Waste processing options

As outlined in the methods section, most nuclear-related LCA studies and reviews were not explicit about the waste treatment/conditioning processes considered within their studies. Moreover, existing reviews of LCA in the nuclear sector (Warner and Heath 2012 ; Nian et al. 2014 ; Lenzen 2008 ) often do not include sections on waste processing.

One major finding of this review is that, in the studies identified, only two studies explicitly mentioned specific processing options as described in Table  3 . Firstly, Guidi et al. ( 2010 ) considered the decontamination of a surface through the use of a peelable gel, concluding that the conditioning, storage and disposal of the waste were the most dominant impacts of the decontamination process. Secondly, Wallbridge et al. ( 2013 ) explicitly described basic decontamination methods: washing with water, detergents or alcohol and ‘more aggressive decontamination’ such as blasting or treatment with chemicals are present within the scope of the LCA. However, in the LCA model produced by that study, these processes were simplified, for instance through the inclusion of a generic ‘soap’ dataset as a substitute for chemical surfactants and the exclusion of mechanical decontamination processes such as shot blasting.

The overall lack of data resolution regarding waste processing options, however, should be addressed by future studies. As more NPPs come offline and the total volume of waste for Europe alone is estimated to be in the region of 3,600,000 m 3 (European Commission 2019 ) by 2030, there should be a clear focus on ascertaining the impacts of not just a blanket policy of geological disposal, but also waste processing and pre-disposal options both developed and developing. Without such analyses, it is not possible for future decision-making in the policy, operations and R&D realms to enhance further the environmental sustainability of waste disposal and processing. Moreover, without greater attention to these life cycle stages in future LCAs, the current understanding of front-end dominance in the overall nuclear power life cycle (outlined in Sect. ‘ LCA results ’) is highly uncertain, which may itself influence policy and operational decisions.

In the absence of other specific waste processing information, an assumption of grouting in steel boxes at low loadings could serve as a conservative default approach, as in the case of Godsey ( 2019 ).

Papers of partial relevance

An LCA by Koltun et al. ( 2018 ) is partially relevant to this review due to its focus on theoretical Gen IV High-Temperature Gas Reactors (HGTR). It included front-end construction and materials, use, back-end and decommissioning and waste disposal as boundary conditions, with a functional unit of 1 MWh electricity generated, which is typical of most LCAs surrounding the nuclear fuel cycle. In line with other studies, commissioning and decommissioning cause most of the global warming potential (GWP) but the construction of waste repositories is also a significant contributor. Basic solid materials are included, but no specific waste disposal or pre-disposal processes are detailed.

The challenge of managing radioactive waste is large and complex, requiring the processing of millions of cubic metres of waste globally over the coming decades. The waste types are varied, with numerous technologies being developed to aid in their processing, and the environmental impacts of these must not be overlooked. Consequently, this paper has systematically reviewed the literature for studies addressing the back-end of the nuclear fuel cycle from a life cycle assessment perspective.

Overall, this literature review has revealed a lack of LCA studies focused on the back-end of the nuclear fuel cycle. Of the limited nuclear-related studies discovered, the focus has predominantly been the full nuclear life cycle or power generation. Though decommissioning is covered in some of the studies reviewed, as it is not the sole focus, granularity of data is insufficient, and comparisons are difficult to draw. For example, of the 72 relevant papers identified, only two (Wallbridge et al. 2013 ) (Guidi et al. 2010 ) are focused on applying LCA to decommissioning processes. This lack of granularity means that there is limited information as to which decommissioning activities and waste processing methods are more negatively impacting the environment than others, or how they might be improved. Addressing these gaps in future LCA studies will allow the nuclear sector to drive targeted, strategic innovation towards more sustainable back-end processes.

Three key findings from this review give rise to three recommendations, as follows. Firstly, far more activity is needed in future to apply LCA to decommissioning and back-end processes, with goals, functional units and system boundaries that are decommissioning-specific: This is important for both the optimisation of legacy waste processing, which is of a significant volume, and for the development of more comprehensive LCAs of the full nuclear fuel cycle for current and future reactor designs. These back-end processes should be delineated as much as possible during data collection and analysis to improve granularity, enabling the identification of specific hotspots and the generation of more precise, useful findings.

Secondly, this review has established that, at the time of writing, the published literature includes few attempts to investigate the environmental impacts of novel treatment/conditioning technologies and those in development using LCA methods, with most prior work focusing on efficiencies and effectiveness of application into the current fuel cycle. As a result, environmental considerations are only being incorporated into the development of new technologies via the narrower perspective of site licensing and local regulation rather than via a more holistic, life cycle perspective. This is likely hindering the overall environmental sustainability of the sector and could be rectified by applying early-stage or anticipatory LCA techniques to guide technology development.

Thirdly, although there is evidence that a greater proportion of impacts during decommissioning may be associated with solid waste types compared to liquid, LCA practitioners should also consider the impacts associated with liquid waste processing and disposal. The vast array of technologies available has made it difficult to conduct meaningful LCA to date. With further attempts to collect data on specific waste processing technologies, LCA could be used to provide valuable insight into the most environmentally favourable options within decision-making processes.

In conclusion, future research should be focused on the collection of more LCA data surrounding back-end nuclear processes. This requires the collection of mass and energy balance information associated with existing and candidate waste processing technologies, enabling the completion of LCA models which can then, in turn, feed into broader LCAs of whole back-end processes as well as full fuel cycle models. Data should be as granular as possible and focus on both solid and liquid waste types. Current state-of-the-art impact assessment methodologies should be adopted to provide a broad range of impacts, and new radiological impact methodologies such as UCrad should be explored further. This will allow LCA practitioners the opportunity to conduct meaningful comparisons between different waste processing/decommissioning scenarios through identification of hotspots. This will ultimately help inform the research agenda of those investigating novel technologies and will aid in the integration of LCA within the nuclear sector.

Data availability

Enquiries about data availability should be directed to the authors.

Abbreviations

Critical group methodology

Functional unit

Geological disposal facility

4Th generation nuclear power plant

Greenhouse gas

Human health damage

High-level waste

International atomic energy agency

Intermediate-level waste

Life cycle assessment

Life cycle costing

Life cycle impact assessment

Low-level waste

Low-level waste repository

Nuclear power plant

Radioactive waste

Small modular reactor

Very low-level waste

Abdel Rahman RO, Ibrahium HA, Hung Y-T (2011) Liquid radioactive wastes treatment: a review. Water 3:551–565

Article   Google Scholar  

Abrahamsen-Mills L, Wareing A, Fowler L, Jarvis R, Norris S, Banford A (2021) Development of a multi criteria decision analysis framework for the assessment of integrated waste management options for irradiated graphite. Nucl Eng Technol 53:1224–1235

Article   CAS   Google Scholar  

Allensworth JR, Simpson MF, Yim MS, Phongikaroon S (2013) Investigation of fission product transport into zeolite-a for pyroprocessing waste minimization. Nucl Technol 181:337–348

Arzoumanidis I, D’Eusanio M, Raggi A, Petti L (2020) Functional unit definition criteria in life cycle assessment and social life cycle assessment: a discussion. Perspectives on social LCA. Springer International Publishing, New York

Book   Google Scholar  

Azapagic A, Clift R, Perdan S, Dawsonera Perdan S, Clift R (2011) Sustainable development in practice : case studies for engineers and scientists. John Wiley & Sons Ltd, Hoboken

Google Scholar  

Bart F, Cau-Di-coumes CL, Frizon F, Lorente S (2013) Cement-based materials for nuclear waste storage. Springer, New York

Benedict RW, Solbrig C, Westphal B, Johnson TA, Li SX, Marsden K, Goff KM (2007) Pyroprocessing progress at Idaho national laboratory. In: GLOBAL 2007: advanced nuclear fuel cycles and systems 741–747

Bourg S, Poinssot C, Geist A, Cassayre L, Rhodes C, Ekberg C (2012) Advanced reprocessing developments in Europe status on European projects ACSEPT and ACTINET-I3. Procedia Chem 7:166–171

Calloway TB, Martino CJ, Jantzen CM, Wilmarth WR, Stone ME, Pierce RA, Josephs JE, Barnes CD, Daniel WE, Eibling RE, Choi AS, White TL, Crowley DA, Baich MA, Johnson JD, Vijayaraghavan K, Nikolov A, Wasan DT (2003) Radioactive waste evaporation: current methodologies employed for the development, design and operation of waste evaporators at the Savannah river site and Hanford waste treatment plant. In: 9th ASME international conference on radioactive waste management and environmental remediation Volumes 1, 2, and 3, 2003-01-01 2003. ASMEDC

Choppin GR, Rydberg J, Liljenzin J, Ekberg, C (2013) Radiochemistry & Nuclear Chemistry, 4th edition, Academic Press, Amsterdam.

Deckers J (2011) Incineration and plasma processes and technology for treatment and conditioning of radioactive waste. Handbook of advanced radioactive waste conditioning technologies. Elsevier, Amsterdam

Ding N, Liu J, Yang J, Yang D (2017) Comparative life cycle assessment of regional electricity supplies in China. Resour Conserv Recycl 119:47–59

U.S. DOE (2022) Best practices for life cycle assessment (LCA) of direct air capture with storage (DACS). In: U.S. Department of energy, O. O. F. E. A. C. M. (ed.)

Drecier M (1995) Externality of energy nuclear energy, vol. 5, European commission (1995). Externality of energy nuclear energy, 5

EC-JRC (2011) International reference life cycle data system (ILCD) handbook – General guide for life cycle assessment: provisions and action steps, Publications Office.

ECOINVENT (2023) Ecoinvent v3.9.1. Switzerland

EDF (2016) Hinkley Point C, Building Britain's Low-carbon Future. EDF

European Commission (2019) Inventory of radioactive waste and spent fuel present in the community’s territory and the future prospects. Report from the commission to the council and the european parliament, Brussels

European Commission (2021) Environmental Footprints methods [Online]. Available: https://green-business.ec.europa.eu/environmental-footprint-methods_en#related-documents . Accessed 2024

European Platform On LCA (2022) Environmental footprint reference packages [Online]. Directorate-general for communication. Available: https://eplca.jrc.ec.europa.eu/LCDN/developerEF.xhtml . Accessed Aug 2023

Frischknecht R, Braunschweig A, Hofstetter P, Suter P (2000) Human health damages due to ionising radiation in life cycle impact assessment. Environ Impact Assess Rev 20:159–189

Fthenakis VM, Kim HC (2007) Greenhouse-gas emissions from solar electric- and nuclear power: a life-cycle study. Energy Policy 35:2549–2557

Gagnon L, Bélanger C, Uchiyama Y (2002) Life-cycle assessment of electricity generation options: the status of research in year 2001. Energy Policy 30:1267–1278

Garamszeghy M (2011) Compaction processes and technology for treatment and conditioning of radioactive waste. Handbook of advanced radioactive waste conditioning technologies. Elsevier, New York

HW Godbee (1973) Use of evaporation for the treatment of liquids in the nuclear industry. Oak Ridge National Laboratory

GODSEY, K. (2019) Life cycle assessment of small modular reactors using us nuclear fuel cycle. Clemson University, Masters

Goedkeep M, Spriensma R (2001) The eco-indicator 99: a damage oriented method for life cycle impact assessment. Third Edition ed

Goedkoop M, Heijungs R, Huijbregts M, Schryver AD, Struijs J, Van Zelm R (2009) A life cycle impact assessment method which comprises harmonized category indicators at the midpoint and the endpoint level. The Hague, Ministry of VROM. ReCiPe

Guidi G, Cumo F, de Santoli L (2010) LCA of strippable coatings and of steam vacuum technology used for nuclear plants decontamination. Clean Technol Environ Policy 12:283–289

Guinée JB, Lindeijer E (2002) Handbook on life cycle assessment: operational guide to the ISO standards. Springer Science & Business Media, Berlin

Hauschild MZ, Goedkoop M, Guinée J, Heijungs R, Huijbregts M, Jolliet O, Margni M, de Schryver A, Humbert S, Laurent A (2013) Identifying best existing practice for characterization modeling in life cycle impact assessment. Int J Life Cycle Assess 18:683–697

Heath P (2017) Hot isostatic pressing can substantially reduce the volume of nuclear waste. Research Features

Hirabayashi T, Kameo Y, Myodo M (2000) Application of a laser to decontamination and decommissioning of nuclear facilities at JAERI, SPIE

Huijbregts MAJ, Steinmann ZJN, Elshout PMF, Stam G, Verones F, Vieira MDM, Hollander A, Zijp M, Van Zelm R (2016) ReCiPe 2016: a harmonized life cycle impact assessment method at midpoint and the endpoint level – Report 1: characterization. Bilthoven, The Netherlands: Dutch National Institute for Public Health and the Environment (RIVM)

IAEA (1992) Design and operation of radioactive waste incineration facilities. International Atomic Energy Agency, Vienna

IAEA (1993) Bituminization processes to condition radioactive wastes. International Atomic Energy Agency, Vienna

IAEA (2002) Application of Ion exchange processes for the treatment of radioactive waste and management of spent ion exchangers. International Atomic Energy Agency, Vienna

IAEA (2004) Application of membrane technologies for liquid radioactive waste processing. International Atomic Energy Agency, Vienna

IAEA (2011) The nuclear fuel cycle

IAEA (2021) Treatment and conditioning of nuclear waste [Online]. UK: IAEA

IEA (2022) Nuclear - fuels and technology [Online]. Available: https://www.iea.org/fuels-and-technologies/nuclear

IPOINT (2018) Life cycle impact assessment – which are the LCIA indicator sets most widely used by practitioners? [Online]. iPoint-systems gmbh Ludwig-Erhard-Str. 58 72760 Reutlingen Germany: iPoint-systems gmbh. Accessed Apr 2022 2022

ISO 2006a. ISO 14040:2006 Environmental management — Life cycle assessment — Principles and framework. In: ISO (ed.) 2 ed

ISO (2006b) ISO 14044:2006. Environmental management - Life cycle assessment - requirements and guidelines. Geneva, Switzerland: International organisation for standardisation

Jolliet O, Margni M, Charles R, Humbert S, Payet J, Rebitzer G, Rosenbaum R (2003) IMPACT 2002+: a new life cycle impact assessment methodology. Int J Life Cycle Assess 8:324–330

KGM (2024) Eora database [Online]. Available: https://www.worldmrio.com/ . Accessed Jul 2024

Kim K, Kim K, Choi M, Son SH, Han JH (2012) Treatment of ion exchange resins used in nuclear power plants by super- and sub-critical water oxidation – a road to commercial plant from bench-scale facility. Chem Eng J 189–190:213–221

Kim JH, Seo EA, Chung KDG, CW, (2021) Utilization of recycled cement powder as a solidifying agent for radioactive waste immobilization. Constr Build Mater 289:123126

Koltun P, Tsykalo A, Novozhilov V (2018) Life cycle assessment of the new generation GT-MHR nuclear power plant. Energies 11:3452

Kriven WM (2021) Geopolymers and geopolymer-derived composites. In: Pomeroy M (ed) Encyclopedia of materials: technical ceramics and glasses. Elsevier, Oxford

Lee YE, Lee KJ, Lee BW (2000) Environmental assessment of nuclear power generation in Korea. Prog Nucl Energy 37:113–118

Lenzen M (2008) Life cycle energy and greenhouse gas emissions of nuclear energy: a review. Energy Convers Manag 49:2178–2199

Lewin RG, Harrison MT (2015) 15 - International developments in electrorefining technologies for pyrochemical processing of spent nuclear fuels. In: Taylor R (ed) Reprocessing and recycling of spent nuclear fuel. Oxford Woodhead Publishing, Sawston

LTD., KAP (2024) Eora database [Online]. Available: https://www.worldmrio.com/

Matsuda M, Nishi T, Tamada S, Kikuchi M, Kato H (1994) Pelletizing method for radioactive waste and solidification method for radioactive waste pellet

Ministry Of Economic Affairs And Employment (2022a) Management of spent nuclear fuel and radioactive waste in finland. Helsinki: vnjulkaisumyynti.f

Ministry Of Economic Affairs And Employment (2022b) Spent nuclear fuel will be disposed of in Finland [Online]. Helsinki, Finland. Available: https://tem.fi/en/spent-nuclear-fuel

Nian V, Chou SK, Su B, Bauly J (2014) Life cycle analysis on carbon emissions from power generation – the nuclear energy example. Appl Energy 118:68–82

Nuclear Decommissioning Authority. 2021. Timing of the magnox reactor decommissioning strategy [Online]. Available: https://www.gov.uk/government/case-studies/timing-of-the-magnox-reactor-decommissioning-strategy . Accessed Dec 2022

Nuclear Decommissioning Authority (2023) UK radioactive waste inventory 2022 [Online]. Nuclear decommissioning authority. Available: https://ukinventory.nda.gov.uk/the-2022-inventory/2022-uk-data/ . Accessed Oct 2023

Nuclear Decommissioning Authority (2024) About Radioactive Waste [Online]. Nuclear Decommissioning Authority. Available: https://ukinventory.nda.gov.uk/about-radioactive-waste/what-is-radioactivity/what-are-the-main-wastecategories/ . Accessed May 2024.

OECD (2022) Green growth and sustainable development [Online]. Available: https://www.oecd.org/greengrowth/ . Accessed Nov 2022

Ojovan MI, Lee WE (2005) Chapter 16 - immobilisation of radioactive wastes in Bitumen. In: Ojovan MI, Lee WE (eds) An introduction to nuclear waste immobilisation. Elsevier, Amsterdam, Oxford

Paulillo A, Clift R, Dodds JM, Milliken A, Lettieri PSJ, P, (2020) Radiological impacts in life cycle assessment. Part I: General framework and two practical methodologies. Sci Total Environ 708:135179

Paulillo A, Dodds JM, Palethorpe SJ, Lettieri P (2021) Reprocessing vs direct disposal of used nuclear fuels: The environmental impacts of future scenarios for the UK. Sustain Mater Technol 28:e00278

CAS   Google Scholar  

Poinssot C, Bourg S, Boullis B (2016) Improving the nuclear energy sustainability by decreasing its environmental footprint. Guidelines from life cycle assessment simulations. Prog Nucl Energy 92:234–241

Pomponi F, Hart J (2021) The greenhouse gas emissions of nuclear energy – life cycle assessment of a European pressurised reactor. Appl Energy 290:116743

Posiva 2021. Operating license application

Reeb C, Pierlot C, Davy C, Lambertin D (2021) Incorporation of organic liquids into geopolymer materials - a review of processing, properties and applications. Ceram Int 47(6):7369–7385

Rosenbaum RK, Hauschild MZ, Boulay A-M, Fantke P, Laurent A, Núñez M, Vieira M (2018) Life cycle impact assessment. In: Hauschild MZ, Olsen SI, Rosenbaum RK (eds) Life cycle assessment theory and practice gewerbestrasse. Springer, Cham

Santoyo-Castelazo E, Gujba H, Azapagic A (2011) Life cycle assessment of electricity generation in Mexico. Energy 36:1488–1499

Sheldon S, Hadian S, Zik O (2015) Beyond carbon: quantifying environmental externalities as energy for hydroelectric and nuclear power. Energy 84:36–44

Siddiqui O, Dincer I (2017) Comparative assessment of the environmental impacts of nuclear, wind and hydro-electric power plants in Ontario: a life cycle assessment. J Clean Prod 164:848–860

Simapro (2024) Simapro databases [Online]. Available: https://support.simapro.com/s/article/Which-databases-are-included-in-SimaPro . Accessed July 2024

SKB (2021) The final repository SFR [Online]. Available: https://www.skb.com/our-operations/sfr/ . Accessed 21Apr 2021

Thorpe CL, Neeway JJ, Pearce CI, Hand RJ, Fisher AJ, Walling SA, Hyatt NC, Kruger AA, Schweiger M, Kosson DS, Arendt CL, Marcial J, Corkhill CL (2021) Forty years of durability assessment of nuclear waste glass by standard methods. Npj Mater Degrad 5(1):61

Turconi R, Boldrin A, Astrup T (2013) Life cycle assessment (LCA) of electricity generation technologies: overview, comparability and limitations. Renew Sustain Energy Rev 28:555–565

VGB Powertech EV (2012) Waste disposal for nuclear power plants. VGB PowerTech e.V, Germany

Vira J (2017) Geological repository for high-level nuclear waste becoming reality in Finland. In: Geological repository systems for safe disposal of spent nuclear fuels and radioactive waste

Wallbridge S, Banford A, Azapagic A (2013) Life cycle environmental impacts of decommissioning Magnox nuclear power plants in the UK. Int J Life Cycle Assess 18:990–1008

Walling SA, Kauffmann MN, Gardner LJ, Bailey DJ, Stennett MC, Corkhill CL, Hyatt NC (2021) Characterisation and disposability assessment of multi-waste stream in-container vitrified products for higher activity radioactive waste. J Hazard Mater 401:123764

Warner ES, Heath GA (2012) Life cycle greenhouse gas emissions of nuclear electricity generation. J Ind Ecol 16:S73–S92

WILLE, H. 1987. System decontamination with cord and decontamination for unrestricted release. Nuclear Power Performance and Safety. Vienna: IAEA

World Nuclear Association (2021) Decommissioning nuclear facilities [Online]. Accessed April 2022 2022

Yamamoto S, Takahashi H, Taniguchi H, Kawashima A, Takahashi H, Kikura H (2020) Fundamental study on decontamination method using shot blasting and barrel polishing for radioactive metal waste. In: 2020 international conference on nuclear engineering collocated with the ASME 2020 power conference, V001T04A014

Download references

Acknowledgements

The authors gratefully acknowledge the funding that enabled this work, received from the EU Horizon 2020 programme and Euratom as part of the PREDIS project (‘Pre-disposal management of radioactive waste’, Euratom research and training programme grant agreement No. 945098).

Author information

Authors and affiliations.

Department of Chemical Engineering, Sustainable Industrial Systems, The University of Manchester, Manchester, UK

Rachael Clayton, Joel Kirk & Laurence Stamford

National Nuclear Laboratory, Warrington, UK

Anthony Banford

You can also search for this author in PubMed   Google Scholar

Contributions

Rachael Clayton helped in conceptualisation, methodology, software, formal analysis, investigation, writing—original draft, visualisation and validation. Joel Kirk helped in conceptualisation, methodology, software, formal analysis, investigation, writing—original draft, visualisation and validation. Anthony Banford helped in conceptualisation, methodology, validation, data curation, writing—review & editing, supervision, project administration and funding acquisition. Laurence Stamford helped in conceptualisation, methodology, validation, data curation, writing—review & editing, supervision, project administration and funding acquisition.

Corresponding author

Correspondence to Laurence Stamford .

Ethics declarations

Conflict of interest.

The authors have no relevant financial or non-financial interests to disclose.

Additional information

Publisher's note.

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ .

Reprints and permissions

About this article

Clayton, R., Kirk, J., Banford, A. et al. A review of radioactive waste processing and disposal from a life cycle environmental perspective. Clean Techn Environ Policy (2024). https://doi.org/10.1007/s10098-024-02998-6

Download citation

Received : 09 May 2024

Accepted : 06 September 2024

Published : 18 September 2024

DOI : https://doi.org/10.1007/s10098-024-02998-6

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Nuclear energy
• Nuclear power
• Decommissioning
• Sustainable engineering
• Find a journal
• Publish with us
• Track your research