a research literature review definition

• 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

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.

Meryl Brodsky : Communication and Information Studies

Hannah Chapman Tripp : Biology, Neuroscience

Carolyn Cunningham : Human Development & Family Sciences, Psychology, Sociology

Larayne Dallas : Engineering

Janelle Hedstrom : Special Education, Curriculum & Instruction, Ed Leadership & Policy ​

Susan Macicak : Linguistics

Imelda Vetter : Dell Medical School

For help in other subject areas, please see the guide to library specialists by subject .

Periodically, UT Libraries runs a workshop covering the basics and library support for literature reviews. While we try to offer these once per academic year, we find providing the recording to be helpful to community members who have missed the session. Following is the most recent recording of the workshop, Conducting a Literature Review. To view the recording, a UT login is required.

• October 26, 2022 recording
• Last Updated: Oct 26, 2022 2:49 PM
• URL: https://guides.lib.utexas.edu/literaturereviews

Libraries | Research Guides

Literature reviews, what is a literature review, learning more about how to do a literature review.

• Planning the Review
• The Research Question
• Choosing Where to Search
• Organizing the Review
• Writing the Review

A literature review is a review and synthesis of existing research on a topic or research question. A literature review is meant to analyze the scholarly literature, make connections across writings and identify strengths, weaknesses, trends, and missing conversations. A literature review should address different aspects of a topic as it relates to your research question. A literature review goes beyond a description or summary of the literature you have read. 

• Sage Research Methods Core Collection This link opens in a new window SAGE Research Methods supports research at all levels by providing material to guide users through every step of the research process. SAGE Research Methods is the ultimate methods library with more than 1000 books, reference works, journal articles, and instructional videos by world-leading academics from across the social sciences, including the largest collection of qualitative methods books available online from any scholarly publisher. – Publisher

• Next: Planning the Review >>
• Last Updated: May 2, 2024 10:39 AM
• URL: https://libguides.northwestern.edu/literaturereviews

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.

Literature Reviews

• Getting started

What is a literature review?

Why conduct a literature review, stages of a literature review, lit reviews: an overview (video), check out these books.

• Types of reviews
• 1. Define your research question
• 2. Plan your search
• 3. Search the literature
• 4. Organize your results
• 5. Synthesize your findings
• 6. Write the review
• Artificial intelligence (AI) tools
• Thompson Writing Studio This link opens in a new window
• Need to write a systematic review? This link opens in a new window

Contact a Librarian

Ask a Librarian

Definition: A literature review is a systematic examination and synthesis of existing scholarly research on a specific topic or subject.

Purpose: It serves to provide a comprehensive overview of the current state of knowledge within a particular field.

Analysis: Involves critically evaluating and summarizing key findings, methodologies, and debates found in academic literature.

Identifying Gaps: Aims to pinpoint areas where there is a lack of research or unresolved questions, highlighting opportunities for further investigation.

Contextualization: Enables researchers to understand how their work fits into the broader academic conversation and contributes to the existing body of knowledge.

tl;dr  A literature review critically examines and synthesizes existing scholarly research and publications on a specific topic to provide a comprehensive understanding of the current state of knowledge in the field.

What is a literature review NOT?

❌ An annotated bibliography

❌ Original research

❌ A summary

❌ Something to be conducted at the end of your research

❌ An opinion piece

❌ A chronological compilation of studies

The reason for conducting a literature review is to:

Literature Reviews: An Overview for Graduate Students

While this 9-minute video from NCSU is geared toward graduate students, it is useful for anyone conducting a literature review.

Writing the literature review: A practical guide

Available 3rd floor of Perkins

Writing literature reviews: A guide for students of the social and behavioral sciences

Available online!

So, you have to write a literature review: A guided workbook for engineers

Telling a research story: Writing a literature review

The literature review: Six steps to success

Systematic approaches to a successful literature review

Request from Duke Medical Center Library

Doing a systematic review: A student's guide

• Next: Types of reviews >>
• Last Updated: May 17, 2024 8:42 AM
• URL: https://guides.library.duke.edu/litreviews

Services for...

• Faculty & Instructors
• Graduate Students
• Undergraduate Students
• International Students
• Patrons with Disabilities

• Harmful Language Statement
• Re-use & Attribution / Privacy
• Support the Libraries

• 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

Have a language expert improve your writing

Run a free plagiarism check in 10 minutes, automatically generate references for free.

• Knowledge Base
• Dissertation
• What is a Literature Review? | Guide, Template, & Examples

What is a Literature Review? | Guide, Template, & Examples

Published on 22 February 2022 by Shona McCombes . Revised on 7 June 2022.

What is a literature review? A literature review is a survey of scholarly sources on a specific topic. It provides an overview of current knowledge, allowing you to identify relevant theories, methods, and gaps in the existing research.

There are five key steps to writing a literature review:

• Search for relevant literature
• Evaluate sources
• Identify themes, debates and gaps
• Outline the structure
• Write your literature review

A good literature review doesn’t just summarise sources – it analyses, synthesises, and critically evaluates to give a clear picture of the state of knowledge on the subject.

Instantly correct all language mistakes in your text

Be assured that you'll submit flawless writing. Upload your document to correct all your mistakes.

Table of contents

Why write a literature review, examples of literature reviews, step 1: search for relevant literature, step 2: evaluate and select sources, step 3: identify themes, debates and gaps, step 4: outline your literature review’s structure, step 5: write your literature review, frequently asked questions about literature reviews, introduction.

• Quick Run-through
• Step 1 & 2

When you write a dissertation or thesis, you will have to conduct a literature review to situate your research within existing knowledge. The literature review gives you a chance to:

• Demonstrate your familiarity with the topic and scholarly context
• Develop a theoretical framework and methodology for your research
• Position yourself in relation to other researchers and theorists
• Show how your dissertation addresses a gap or contributes to a debate

You might also have to write a literature review as a stand-alone assignment. In this case, the purpose is to evaluate the current state of research and demonstrate your knowledge of scholarly debates around a topic.

The content will look slightly different in each case, but the process of conducting a literature review follows the same steps. We’ve written a step-by-step guide that you can follow below.

The only proofreading tool specialized in correcting academic writing

The academic proofreading tool has been trained on 1000s of academic texts and by native English editors. Making it the most accurate and reliable proofreading tool for students.

Correct my document today

Writing literature reviews can be quite challenging! A good starting point could be to look at some examples, depending on what kind of literature review you’d like to write.

• Example literature review #1: “Why Do People Migrate? A Review of the Theoretical Literature” ( Theoretical literature review about the development of economic migration theory from the 1950s to today.)
• Example literature review #2: “Literature review as a research methodology: An overview and guidelines” ( Methodological literature review about interdisciplinary knowledge acquisition and production.)
• Example literature review #3: “The Use of Technology in English Language Learning: A Literature Review” ( Thematic literature review about the effects of technology on language acquisition.)
• Example literature review #4: “Learners’ Listening Comprehension Difficulties in English Language Learning: A Literature Review” ( Chronological literature review about how the concept of listening skills has changed over time.)

You can also check out our templates with literature review examples and sample outlines at the links below.

Download Word doc Download Google doc

Before you begin searching for literature, you need a clearly defined topic .

If you are writing the literature review section of a dissertation or research paper, you will search for literature related to your research objectives and questions .

If you are writing a literature review as a stand-alone assignment, you will have to choose a focus and develop a central question to direct your search. Unlike a dissertation research question, this question has to be answerable without collecting original data. You should be able to answer it based only on a review of existing publications.

Make a list of keywords

Start by creating a list of keywords related to your research topic. Include each of the key concepts or variables you’re interested in, and list any synonyms and related terms. You can add to this list if you discover new keywords in the process of your literature search.

• Social media, Facebook, Instagram, Twitter, Snapchat, TikTok
• Body image, self-perception, self-esteem, mental health
• Generation Z, teenagers, adolescents, youth

Search for relevant sources

Use your keywords to begin searching for sources. Some databases to search for journals and articles include:

• Your university’s library catalogue
• Google Scholar
• Project Muse (humanities and social sciences)
• Medline (life sciences and biomedicine)
• EconLit (economics)
• Inspec (physics, engineering and computer science)

You can use boolean operators to help narrow down your search:

Read the abstract to find out whether an article is relevant to your question. When you find a useful book or article, you can check the bibliography to find other relevant sources.

To identify the most important publications on your topic, take note of recurring citations. If the same authors, books or articles keep appearing in your reading, make sure to seek them out.

You probably won’t be able to read absolutely everything that has been written on the topic – you’ll have to evaluate which sources are most relevant to your questions.

For each publication, ask yourself:

• What question or problem is the author addressing?
• What are the key concepts and how are they defined?
• What are the key theories, models and methods? Does the research use established frameworks or take an innovative approach?
• What are the results and conclusions of the study?
• How does the publication relate to other literature in the field? Does it confirm, add to, or challenge established knowledge?
• How does the publication contribute to your understanding of the topic? What are its key insights and arguments?
• What are the strengths and weaknesses of the research?

Make sure the sources you use are credible, and make sure you read any landmark studies and major theories in your field of research.

You can find out how many times an article has been cited on Google Scholar – a high citation count means the article has been influential in the field, and should certainly be included in your literature review.

The scope of your review will depend on your topic and discipline: in the sciences you usually only review recent literature, but in the humanities you might take a long historical perspective (for example, to trace how a concept has changed in meaning over time).

Remember that you can use our template to summarise and evaluate sources you’re thinking about using!

Take notes and cite your sources

As you read, you should also begin the writing process. Take notes that you can later incorporate into the text of your literature review.

It’s important to keep track of your sources with references to avoid plagiarism . It can be helpful to make an annotated bibliography, where you compile full reference information and write a paragraph of summary and analysis for each source. This helps you remember what you read and saves time later in the process.

You can use our free APA Reference Generator for quick, correct, consistent citations.

To begin organising your literature review’s argument and structure, you need to understand the connections and relationships between the sources you’ve read. Based on your reading and notes, you can look for:

• Trends and patterns (in theory, method or results): do certain approaches become more or less popular over time?
• Themes: what questions or concepts recur across the literature?
• Debates, conflicts and contradictions: where do sources disagree?
• Pivotal publications: are there any influential theories or studies that changed the direction of the field?
• Gaps: what is missing from the literature? Are there weaknesses that need to be addressed?

This step will help you work out the structure of your literature review and (if applicable) show how your own research will contribute to existing knowledge.

• Most research has focused on young women.
• There is an increasing interest in the visual aspects of social media.
• But there is still a lack of robust research on highly-visual platforms like Instagram and Snapchat – this is a gap that you could address in your own research.

There are various approaches to organising the body of a literature review. You should have a rough idea of your strategy before you start writing.

Depending on the length of your literature review, you can combine several of these strategies (for example, your overall structure might be thematic, but each theme is discussed chronologically).

Chronological

The simplest approach is to trace the development of the topic over time. However, if you choose this strategy, be careful to avoid simply listing and summarising sources in order.

Try to analyse patterns, turning points and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred.

If you have found some recurring central themes, you can organise your literature review into subsections that address different aspects of the topic.

For example, if you are reviewing literature about inequalities in migrant health outcomes, key themes might include healthcare policy, language barriers, cultural attitudes, legal status, and economic access.

Methodological

If you draw your sources from different disciplines or fields that use a variety of research methods , you might want to compare the results and conclusions that emerge from different approaches. For example:

• Look at what results have emerged in qualitative versus quantitative research
• Discuss how the topic has been approached by empirical versus theoretical scholarship
• Divide the literature into sociological, historical, and cultural sources

Theoretical

A literature review is often the foundation for a theoretical framework . You can use it to discuss various theories, models, and definitions of key concepts.

You might argue for the relevance of a specific theoretical approach, or combine various theoretical concepts to create a framework for your research.

Like any other academic text, your literature review should have an introduction , a main body, and a conclusion . What you include in each depends on the objective of your literature review.

The introduction should clearly establish the focus and purpose of the literature review.

If you are writing the literature review as part of your dissertation or thesis, reiterate your central problem or research question and give a brief summary of the scholarly context. You can emphasise the timeliness of the topic (“many recent studies have focused on the problem of x”) or highlight a gap in the literature (“while there has been much research on x, few researchers have taken y into consideration”).

Depending on the length of your literature review, you might want to divide the body into subsections. You can use a subheading for each theme, time period, or methodological approach.

As you write, make sure to follow these tips:

• Summarise and synthesise: give an overview of the main points of each source and combine them into a coherent whole.
• Analyse and interpret: don’t just paraphrase other researchers – add your own interpretations, 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 transitions and topic sentences to draw connections, comparisons and contrasts.

In the conclusion, you should summarise the key findings you have taken from the literature and emphasise their significance.

If the literature review is part of your dissertation or thesis, reiterate how your research addresses gaps and contributes new knowledge, or discuss how you have drawn on existing theories and methods to build a framework for your research. This can lead directly into your methodology section.

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 dissertation , thesis, research paper , or proposal .

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

• To familiarise 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.

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

Cite this Scribbr article

If you want to cite this source, you can copy and paste the citation or click the ‘Cite this Scribbr article’ button to automatically add the citation to our free Reference Generator.

McCombes, S. (2022, June 07). What is a Literature Review? | Guide, Template, & Examples. Scribbr. Retrieved 26 May 2024, from https://www.scribbr.co.uk/thesis-dissertation/literature-review/

Is this article helpful?

Shona McCombes

Other students also liked, how to write a dissertation proposal | a step-by-step guide, what is a theoretical framework | a step-by-step guide, what is a research methodology | steps & tips.

Reference management. Clean and simple.

What is a literature review? [with examples]

What is a literature review?

The purpose of a literature review, how to write a literature review, the format of a literature review, general formatting rules, the length of a literature review, literature review examples, frequently asked questions about literature reviews, related articles.

A literature review is an assessment of the sources in a chosen topic of research.

In a literature review, you’re expected to report on the existing scholarly conversation, without adding new contributions.

If you are currently writing one, you've come to the right place. In the following paragraphs, we will explain:

• the objective of a literature review
• how to write a literature review
• the basic format of a literature review

Tip: It’s not always mandatory to add a literature review in a paper. Theses and dissertations often include them, whereas research papers may not. Make sure to consult with your instructor for exact requirements.

The four main objectives of a literature review are:

• Studying the references of your research area
• Summarizing the main arguments
• Identifying current gaps, stances, and issues
• Presenting all of the above in a text

Ultimately, the main goal of a literature review is to provide the researcher with sufficient knowledge about the topic in question so that they can eventually make an intervention.

The format of a literature review is fairly standard. It includes an:

• introduction that briefly introduces the main topic
• body that includes the main discussion of the key arguments
• conclusion that highlights the gaps and issues of the literature

➡️ Take a look at our guide on how to write a literature review to learn more about how to structure a literature review.

First of all, a literature review should have its own labeled section. You should indicate clearly in the table of contents where the literature can be found, and you should label this section as “Literature Review.”

➡️ For more information on writing a thesis, visit our guide on how to structure a thesis .

There is no set amount of words for a literature review, so the length depends on the research. If you are working with a large amount of sources, it will be long. If your paper does not depend entirely on references, it will be short.

Take a look at these three theses featuring great literature reviews:

• School-Based Speech-Language Pathologist's Perceptions of Sensory Food Aversions in Children [ PDF , see page 20]
• Who's Writing What We Read: Authorship in Criminological Research [ PDF , see page 4]
• A Phenomenological Study of the Lived Experience of Online Instructors of Theological Reflection at Christian Institutions Accredited by the Association of Theological Schools [ PDF , see page 56]

Literature reviews are most commonly found in theses and dissertations. However, you find them in research papers as well.

There is no set amount of words for a literature review, so the length depends on the research. If you are working with a large amount of sources, then it will be long. If your paper does not depend entirely on references, then it will be short.

No. A literature review should have its own independent section. You should indicate clearly in the table of contents where the literature review can be found, and label this section as “Literature Review.”

The main goal of a literature review is to provide the researcher with sufficient knowledge about the topic in question so that they can eventually make an intervention.

• University of Oregon Libraries
• Research Guides

How to Write a Literature Review

What's a literature review.

• Literature Reviews: A Recap
• Reading Journal Articles
• Does it Describe a Literature Review?
• 1. Identify the Question
• 2. Review Discipline Styles
• Searching Article Databases
• Finding Full-Text of an Article
• Citation Chaining
• When to Stop Searching
• 4. Manage Your References
• 5. Critically Analyze and Evaluate
• 6. Synthesize
• 7. Write a Literature Review

What's a Literature Review? 

A literature review (or "lit review," for short) is an in-depth critical analysis of published scholarly research related to a specific topic. Published scholarly research (aka, "the literature") may include journal articles, books, book chapters, dissertations and thesis, or conference proceedings. 

A solid lit review must:

• be organized around and related directly to the thesis or research question you're developing
• synthesize results into a summary of what is and is not known
• identify areas of controversy in the literature
• formulate questions that need further research

• << Previous: Start
• Next: Literature Reviews: A Recap >>
• Last Updated: May 3, 2024 5:17 PM
• URL: https://researchguides.uoregon.edu/litreview

Contact Us Library Accessibility UO Libraries Privacy Notices and Procedures

1501 Kincaid Street Eugene, OR 97403 P: 541-346-3053 F: 541-346-3485

• Visit us on Facebook
• Visit us on Twitter
• Visit us on Youtube
• Visit us on Instagram
• Report a Concern
• Nondiscrimination and Title IX
• Accessibility
• Privacy Policy
• Find People

• 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: May 25, 2024 4:09 PM
• URL: https://libguides.usc.edu/writingguide

• Subject List
• Take a Tour
• For Authors
• Subscriber Services
• Publications
• African American Studies
• African Studies
• American Literature
• Anthropology
• Architecture Planning and Preservation
• Art History
• Atlantic History
• Biblical Studies
• British and Irish Literature
• Childhood Studies
• Chinese Studies
• Cinema and Media Studies
• Communication
• Criminology
• Environmental Science
• Evolutionary Biology
• International Law
• International Relations
• Islamic Studies
• Jewish Studies
• Latin American Studies
• Latino Studies
• Linguistics
• Literary and Critical Theory
• Medieval Studies
• Military History
• Political Science
• Public Health
• Renaissance and Reformation
• Social Work
• Urban Studies
• Victorian Literature
• Browse All Subjects

How to Subscribe

• Free Trials

In This Article Expand or collapse the "in this article" section Literature Reviews

Introduction, what is a literature review.

• Literature Reviews for Thesis or Dissertation
• Stand-alone and Systemic Reviews
• Purposes of a Literature Review
• Texts on Conducting a Literature Review
• Identifying the Research Topic
• The Persuasive Argument
• Searching the Literature
• Creating a Synthesis
• Critiquing the Literature
• Building the Case for the Literature Review Document
• Presenting the Literature Review

Related Articles Expand or collapse the "related articles" section about

About related articles close popup.

Lorem Ipsum Sit Dolor Amet

Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Aliquam ligula odio, euismod ut aliquam et, vestibulum nec risus. Nulla viverra, arcu et iaculis consequat, justo diam ornare tellus, semper ultrices tellus nunc eu tellus.

• Higher Education Research
• Meta-Analysis and Research Synthesis in Education
• Methodologies for Conducting Education Research
• Mixed Methods Research
• Philosophy of Education
• Politics of Education
• Qualitative Data Analysis Techniques

Other Subject Areas

Forthcoming articles expand or collapse the "forthcoming articles" section.

• Black Women in Academia
• Girls' Education in the Developing World
• History of Education in Europe
• Find more forthcoming articles...
• Export Citations
• Share This Facebook LinkedIn Twitter

Literature Reviews by Lawrence A. Machi , Brenda T. McEvoy LAST REVIEWED: 27 October 2016 LAST MODIFIED: 27 October 2016 DOI: 10.1093/obo/9780199756810-0169

Literature reviews play a foundational role in the development and execution of a research project. They provide access to the academic conversation surrounding the topic of the proposed study. By engaging in this scholarly exercise, the researcher is able to learn and to share knowledge about the topic. The literature review acts as the springboard for new research, in that it lays out a logically argued case, founded on a comprehensive understanding of the current state of knowledge about the topic. The case produced provides the justification for the research question or problem of a proposed study, and the methodological scheme best suited to conduct the research. It can also be a research project in itself, arguing policy or practice implementation, based on a comprehensive analysis of the research in a field. The term literature review can refer to the output or the product of a review. It can also refer to the process of Conducting a Literature Review . Novice researchers, when attempting their first research projects, tend to ask two questions: What is a Literature Review? How do you do one? While this annotated bibliography is neither definitive nor exhaustive in its treatment of the subject, it is designed to provide a beginning researcher, who is pursuing an academic degree, an entry point for answering the two previous questions. The article is divided into two parts. The first four sections of the article provide a general overview of the topic. They address definitions, types, purposes, and processes for doing a literature review. The second part presents the process and procedures for doing a literature review. Arranged in a sequential fashion, the remaining eight sections provide references addressing each step of the literature review process. References included in this article were selected based on their ability to assist the beginning researcher. Additionally, the authors attempted to include texts from various disciplines in social science to present various points of view on the subject.

Novice researchers often have a misguided perception of how to do a literature review and what the document should contain. Literature reviews are not narrative annotated bibliographies nor book reports (see Bruce 1994 ). Their form, function, and outcomes vary, due to how they depend on the research question, the standards and criteria of the academic discipline, and the orthodoxies of the research community charged with the research. The term literature review can refer to the process of doing a review as well as the product resulting from conducting a review. The product resulting from reviewing the literature is the concern of this section. Literature reviews for research studies at the master’s and doctoral levels have various definitions. Machi and McEvoy 2016 presents a general definition of a literature review. Lambert 2012 defines a literature review as a critical analysis of what is known about the study topic, the themes related to it, and the various perspectives expressed regarding the topic. Fink 2010 defines a literature review as a systematic review of existing body of data that identifies, evaluates, and synthesizes for explicit presentation. Jesson, et al. 2011 defines the literature review as a critical description and appraisal of a topic. Hart 1998 sees the literature review as producing two products: the presentation of information, ideas, data, and evidence to express viewpoints on the nature of the topic, as well as how it is to be investigated. When considering literature reviews beyond the novice level, Ridley 2012 defines and differentiates the systematic review from literature reviews associated with primary research conducted in academic degree programs of study, including stand-alone literature reviews. Cooper 1998 states the product of literature review is dependent on the research study’s goal and focus, and defines synthesis reviews as literature reviews that seek to summarize and draw conclusions from past empirical research to determine what issues have yet to be resolved. Theoretical reviews compare and contrast the predictive ability of theories that explain the phenomenon, arguing which theory holds the most validity in describing the nature of that phenomenon. Grant and Booth 2009 identified fourteen types of reviews used in both degree granting and advanced research projects, describing their attributes and methodologies.

Bruce, Christine Susan. 1994. Research students’ early experiences of the dissertation literature review. Studies in Higher Education 19.2: 217–229.

DOI: 10.1080/03075079412331382057

A phenomenological analysis was conducted with forty-one neophyte research scholars. The responses to the questions, “What do you mean when you use the words literature review?” and “What is the meaning of a literature review for your research?” identified six concepts. The results conclude that doing a literature review is a problem area for students.

Cooper, Harris. 1998. Synthesizing research . Vol. 2. 3d ed. Thousand Oaks, CA: SAGE.

The introductory chapter of this text provides a cogent explanation of Cooper’s understanding of literature reviews. Chapter 4 presents a comprehensive discussion of the synthesis review. Chapter 5 discusses meta-analysis and depth.

Fink, Arlene. 2010. Conducting research literature reviews: From the Internet to paper . 3d ed. Los Angeles: SAGE.

The first chapter of this text (pp. 1–16) provides a short but clear discussion of what a literature review is in reference to its application to a broad range of social sciences disciplines and their related professions.

Grant, Maria J., and Andrew Booth. 2009. A typology of reviews: An analysis of 14 review types and associated methodologies. Health Information & Libraries Journal 26.2: 91–108. Print.

DOI: 10.1111/j.1471-1842.2009.00848.x

This article reports a scoping review that was conducted using the “Search, Appraisal, Synthesis, and Analysis” (SALSA) framework. Fourteen literature review types and associated methodology make up the resulting typology. Each type is described by its key characteristics and analyzed for its strengths and weaknesses.

Hart, Chris. 1998. Doing a literature review: Releasing the social science research imagination . London: SAGE.

Chapter 1 of this text explains Hart’s definition of a literature review. Additionally, it describes the roles of the literature review, the skills of a literature reviewer, and the research context for a literature review. Of note is Hart’s discussion of the literature review requirements for master’s degree and doctoral degree work.

Jesson, Jill, Lydia Matheson, and Fiona M. Lacey. 2011. Doing your literature review: Traditional and systematic techniques . Los Angeles: SAGE.

Chapter 1: “Preliminaries” provides definitions of traditional and systematic reviews. It discusses the differences between them. Chapter 5 is dedicated to explaining the traditional review, while Chapter 7 explains the systematic review. Chapter 8 provides a detailed description of meta-analysis.

Lambert, Mike. 2012. A beginner’s guide to doing your education research project . Los Angeles: SAGE.

Chapter 6 (pp. 79–100) presents a thumbnail sketch for doing a literature review.

Machi, Lawrence A., and Brenda T. McEvoy. 2016. The literature review: Six steps to success . 3d ed. Thousand Oaks, CA: Corwin.

The introduction of this text differentiates between a simple and an advanced review and concisely defines a literature review.

Ridley, Diana. 2012. The literature review: A step-by-step guide for students . 2d ed. Sage Study Skills. London: SAGE.

In the introductory chapter, Ridley reviews many definitions of the literature review, literature reviews at the master’s and doctoral level, and placement of literature reviews within the thesis or dissertation document. She also defines and differentiates literature reviews produced for degree-affiliated research from the more advanced systematic review projects.

back to top

Users without a subscription are not able to see the full content on this page. Please subscribe or login .

Oxford Bibliographies Online is available by subscription and perpetual access to institutions. For more information or to contact an Oxford Sales Representative click here .

• About Education »
• Meet the Editorial Board »
• Academic Achievement
• Academic Audit for Universities
• Academic Freedom and Tenure in the United States
• Action Research in Education
• Adjuncts in Higher Education in the United States
• Administrator Preparation
• Adolescence
• Advanced Placement and International Baccalaureate Courses
• Advocacy and Activism in Early Childhood
• African American Racial Identity and Learning
• Alaska Native Education
• Alternative Certification Programs for Educators
• Alternative Schools
• American Indian Education
• Animals in Environmental Education
• Art Education
• Artificial Intelligence and Learning
• Assessing School Leader Effectiveness
• Assessment, Behavioral
• Assessment, Educational
• Assessment in Early Childhood Education
• Assistive Technology
• Augmented Reality in Education
• Beginning-Teacher Induction
• Bilingual Education and Bilingualism
• Black Undergraduate Women: Critical Race and Gender Perspe...
• Blended Learning
• Case Study in Education Research
• Changing Professional and Academic Identities
• Character Education
• Children’s and Young Adult Literature
• Children's Beliefs about Intelligence
• Children's Rights in Early Childhood Education
• Citizenship Education
• Civic and Social Engagement of Higher Education
• Classroom Learning Environments: Assessing and Investigati...
• Classroom Management
• Coherent Instructional Systems at the School and School Sy...
• College Admissions in the United States
• College Athletics in the United States
• Community Relations
• Comparative Education
• Computer-Assisted Language Learning
• Computer-Based Testing
• Conceptualizing, Measuring, and Evaluating Improvement Net...
• Continuous Improvement and "High Leverage" Educational Pro...
• Counseling in Schools
• Critical Approaches to Gender in Higher Education
• Critical Perspectives on Educational Innovation and Improv...
• Critical Race Theory
• Crossborder and Transnational Higher Education
• Cross-National Research on Continuous Improvement
• Cross-Sector Research on Continuous Learning and Improveme...
• Cultural Diversity in Early Childhood Education
• Culturally Responsive Leadership
• Culturally Responsive Pedagogies
• Culturally Responsive Teacher Education in the United Stat...
• Curriculum Design
• Data Collection in Educational Research
• Data-driven Decision Making in the United States
• Deaf Education
• Desegregation and Integration
• Design Thinking and the Learning Sciences: Theoretical, Pr...
• Development, Moral
• Dialogic Pedagogy
• Digital Age Teacher, The
• Digital Citizenship
• Digital Divides
• Disabilities
• Distance Learning
• Distributed Leadership
• Doctoral Education and Training
• Early Childhood Education and Care (ECEC) in Denmark
• Early Childhood Education and Development in Mexico
• Early Childhood Education in Aotearoa New Zealand
• Early Childhood Education in Australia
• Early Childhood Education in China
• Early Childhood Education in Europe
• Early Childhood Education in Sub-Saharan Africa
• Early Childhood Education in Sweden
• Early Childhood Education Pedagogy
• Early Childhood Education Policy
• Early Childhood Education, The Arts in
• Early Childhood Mathematics
• Early Childhood Science
• Early Childhood Teacher Education
• Early Childhood Teachers in Aotearoa New Zealand
• Early Years Professionalism and Professionalization Polici...
• Economics of Education
• Education For Children with Autism
• Education for Sustainable Development
• Education Leadership, Empirical Perspectives in
• Education of Native Hawaiian Students
• Education Reform and School Change
• Educational Statistics for Longitudinal Research
• Educator Partnerships with Parents and Families with a Foc...
• Emotional and Affective Issues in Environmental and Sustai...
• Emotional and Behavioral Disorders
• English as an International Language for Academic Publishi...
• Environmental and Science Education: Overlaps and Issues
• Environmental Education
• Environmental Education in Brazil
• Epistemic Beliefs
• Equity and Improvement: Engaging Communities in Educationa...
• Equity, Ethnicity, Diversity, and Excellence in Education
• Ethical Research with Young Children
• Ethics and Education
• Ethics of Teaching
• Ethnic Studies
• Evidence-Based Communication Assessment and Intervention
• Family and Community Partnerships in Education
• Family Day Care
• Federal Government Programs and Issues
• Feminization of Labor in Academia
• Finance, Education
• Financial Aid
• Formative Assessment
• Future-Focused Education
• Gender and Achievement
• Gender and Alternative Education
• Gender, Power and Politics in the Academy
• Gender-Based Violence on University Campuses
• Gifted Education
• Global Mindedness and Global Citizenship Education
• Global University Rankings
• Governance, Education
• Grounded Theory
• Growth of Effective Mental Health Services in Schools in t...
• Higher Education and Globalization
• Higher Education and the Developing World
• Higher Education Faculty Characteristics and Trends in the...
• Higher Education Finance
• Higher Education Governance
• Higher Education Graduate Outcomes and Destinations
• Higher Education in Africa
• Higher Education in China
• Higher Education in Latin America
• Higher Education in the United States, Historical Evolutio...
• Higher Education, International Issues in
• Higher Education Management
• Higher Education Policy
• Higher Education Student Assessment
• High-stakes Testing
• History of Early Childhood Education in the United States
• History of Education in the United States
• History of Technology Integration in Education
• Homeschooling
• Inclusion in Early Childhood: Difference, Disability, and ...
• Inclusive Education
• Indigenous Education in a Global Context
• Indigenous Learning Environments
• Indigenous Students in Higher Education in the United Stat...
• Infant and Toddler Pedagogy
• Inservice Teacher Education
• Integrating Art across the Curriculum
• Intelligence
• Intensive Interventions for Children and Adolescents with ...
• International Perspectives on Academic Freedom
• Intersectionality and Education
• Knowledge Development in Early Childhood
• Leadership Development, Coaching and Feedback for
• Leadership in Early Childhood Education
• Leadership Training with an Emphasis on the United States
• Learning Analytics in Higher Education
• Learning Difficulties
• Learning, Lifelong
• Learning, Multimedia
• Learning Strategies
• Legal Matters and Education Law
• LGBT Youth in Schools
• Linguistic Diversity
• Linguistically Inclusive Pedagogy
• Literacy Development and Language Acquisition
• Literature Reviews
• Mathematics Identity
• Mathematics Instruction and Interventions for Students wit...
• Mathematics Teacher Education
• Measurement for Improvement in Education
• Measurement in Education in the United States
• Methodological Approaches for Impact Evaluation in Educati...
• Mindfulness, Learning, and Education
• Motherscholars
• Multiliteracies in Early Childhood Education
• Multiple Documents Literacy: Theory, Research, and Applica...
• Multivariate Research Methodology
• Museums, Education, and Curriculum
• Music Education
• Narrative Research in Education
• Native American Studies
• Nonformal and Informal Environmental Education
• Note-Taking
• Numeracy Education
• One-to-One Technology in the K-12 Classroom
• Online Education
• Open Education
• Organizing for Continuous Improvement in Education
• Organizing Schools for the Inclusion of Students with Disa...
• Outdoor Play and Learning
• Outdoor Play and Learning in Early Childhood Education
• Pedagogical Leadership
• Pedagogy of Teacher Education, A
• Performance Objectives and Measurement
• Performance-based Research Assessment in Higher Education
• Performance-based Research Funding
• Phenomenology in Educational Research
• Physical Education
• Podcasts in Education
• Policy Context of United States Educational Innovation and...
• Portable Technology Use in Special Education Programs and ...
• Post-humanism and Environmental Education
• Pre-Service Teacher Education
• Problem Solving
• Productivity and Higher Education
• Professional Development
• Professional Learning Communities
• Program Evaluation
• Programs and Services for Students with Emotional or Behav...
• Psychology Learning and Teaching
• Psychometric Issues in the Assessment of English Language ...
• Qualitative, Quantitative, and Mixed Methods Research Samp...
• Qualitative Research Design
• Quantitative Research Designs in Educational Research
• Queering the English Language Arts (ELA) Writing Classroom
• Race and Affirmative Action in Higher Education
• Reading Education
• Refugee and New Immigrant Learners
• Relational and Developmental Trauma and Schools
• Relational Pedagogies in Early Childhood Education
• Reliability in Educational Assessments
• Religion in Elementary and Secondary Education in the Unit...
• Researcher Development and Skills Training within the Cont...
• Research-Practice Partnerships in Education within the Uni...
• Response to Intervention
• Restorative Practices
• Risky Play in Early Childhood Education
• Scale and Sustainability of Education Innovation and Impro...
• Scaling Up Research-based Educational Practices
• School Accreditation
• School Choice
• School Culture
• School District Budgeting and Financial Management in the ...
• School Improvement through Inclusive Education
• School Reform
• Schools, Private and Independent
• School-Wide Positive Behavior Support
• Science Education
• Secondary to Postsecondary Transition Issues
• Self-Regulated Learning
• Self-Study of Teacher Education Practices
• Service-Learning
• Severe Disabilities
• Single Salary Schedule
• Single-sex Education
• Single-Subject Research Design
• Social Context of Education
• Social Justice
• Social Network Analysis
• Social Pedagogy
• Social Science and Education Research
• Social Studies Education
• Sociology of Education
• Standards-Based Education
• Statistical Assumptions
• Student Access, Equity, and Diversity in Higher Education
• Student Assignment Policy
• Student Engagement in Tertiary Education
• Student Learning, Development, Engagement, and Motivation ...
• Student Participation
• Student Voice in Teacher Development
• Sustainability Education in Early Childhood Education
• Sustainability in Early Childhood Education
• Sustainability in Higher Education
• Teacher Beliefs and Epistemologies
• Teacher Collaboration in School Improvement
• Teacher Evaluation and Teacher Effectiveness
• Teacher Preparation
• Teacher Training and Development
• Teacher Unions and Associations
• Teacher-Student Relationships
• Teaching Critical Thinking
• Technologies, Teaching, and Learning in Higher Education
• Technology Education in Early Childhood
• Technology, Educational
• Technology-based Assessment
• The Bologna Process
• The Regulation of Standards in Higher Education
• Theories of Educational Leadership
• Three Conceptions of Literacy: Media, Narrative, and Gamin...
• Tracking and Detracking
• Traditions of Quality Improvement in Education
• Transformative Learning
• Transitions in Early Childhood Education
• Tribally Controlled Colleges and Universities in the Unite...
• Understanding the Psycho-Social Dimensions of Schools and ...
• University Faculty Roles and Responsibilities in the Unite...
• Using Ethnography in Educational Research
• Value of Higher Education for Students and Other Stakehold...
• Virtual Learning Environments
• Vocational and Technical Education
• Wellness and Well-Being in Education
• Women's and Gender Studies
• Young Children and Spirituality
• Young Children's Learning Dispositions
• Young Children's Working Theories
• Privacy Policy
• Cookie Policy
• Legal Notice
• Accessibility

Powered by:

• [66.249.64.20|185.80.149.115]
• 185.80.149.115

Want to create or adapt books like this? Learn more about how Pressbooks supports open publishing practices.

What is a literature review?

A literature review is a critical analysis of the literature related to your research topic. It evaluates and critiques the literature to establish a theoretical framework for your research topic and/or identify a gap in the existing research that your research will address.

A literature review is not a summary of the literature. You need to engage deeply and critically with the literature. Your literature review should show your understanding of the literature related to your research topic and lead to presenting a rationale for your research.

A literature review focuses on:

• the context of the topic
• key concepts, ideas, theories and methodologies
• key researchers, texts and seminal works
• major issues and debates
• identifying conflicting evidence
• the main questions that have been asked around the topic
• the organisation of knowledge on the topic
• definitions, particularly those that are contested
• showing how your research will advance scholarly knowledge (generally referred to as identifying the ‘gap’).

This module will guide you through the functions of a literature review; the typical process of conducting a literature review (including searching for literature and taking notes); structuring your literature review within your thesis and organising its internal ideas; and styling the language of your literature review.

The purposes of a literature review

A literature review serves two main purposes:

1) To show awareness of the present state of knowledge in a particular field, including:

• seminal authors
• the main empirical research
• theoretical positions
• controversies
• breakthroughs as well as links to other related areas of knowledge.

2) To provide a foundation for the author’s research. To do that, the literature review needs to:

• help the researcher define a hypothesis or a research question, and how answering the question will contribute to the body of knowledge;
• provide a rationale for investigating the problem and the selected methodology;
• provide a particular theoretical lens, support the argument, or identify gaps.

Before you engage further with this module, try the quiz below to see how much you already know about literature reviews.

Research and Writing Skills for Academic and Graduate Researchers Copyright © 2022 by RMIT University is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License , except where otherwise noted.

Share This Book

WashU Libraries

Library services for undergraduate research.

• Creating an Abstract
• What is a Literature Review?
• Creating a Poster
• Presenting Your Research
• Share Your Undergraduate Research
• Contact a Subject Librarian This link opens in a new window
• Conducting Research
• College Writing: Citizen Scientist

Literature Review: A Definition

What is a literature review, then.

A literature review discusses and analyses published information in a particular subject area.   Sometimes the information covers a certain time period.

A literature review is more than a summary of the sources, it has an organizational pattern that 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?

While the main focus of an academic research paper is to support your own argument, the focus of a literature review is to summarize and synthesize the arguments and ideas of others. The academic research paper also covers a range of sources, but it is usually a select number of sources, because the emphasis is on the argument. Likewise, a literature review can also have an "argument," but it is not as important as covering a number of sources. In short, an academic research paper and a literature review contain some of the same elements. In fact, many academic research papers will contain a literature review section. What aspect of the study (either the argument or the sources) that is emphasized determines what type of document it is.

( "Literature Reviews" from The Writing Center, University of North Carolina at Chapel Hill )

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.

Journal Articles on Writing Literature Reviews

• Research Methods for Comprehensive Science Literature Reviews Author: Brown,Barry N. Journal: Issues in Science & Technology Librarianship Date: Spring2009 Issue: 57 Page: 1 more... less... Finding some information on most topics is easy. There are abundant sources of information readily available. However, completing a comprehensive literature review on a particular topic is often difficult, laborious, and time intensive; the project requires organization, persistence, and an understanding of the scholarly communication and publishing process. This paper briefly outlines methods of conducting a comprehensive literature review for science topics. [ABSTRACT FROM AUTHOR];
• Research: Considerations in Writing a Literature Review Authors: Black,K. Journal: The New Social Worker Date: 01/01; 2007 Volume: 14 Issue: 2 Page: 12 more... less... Literature reviews are ubiquitous in academic journals, scholarly reports, and social work education. Conducting and writing a good literature review is both personally and professionally satisfying. (Journal abstract).
• How to do (or not to do) A Critical Literature Review Authors: Jesson,Jill; Lacey,Fiona Journal: Pharmacy Education Pub Date: 2006 Volume: 6 Issue: 2 Pages:139 - 148 more... less... More and more students are required to perform a critical literature review as part of their undergraduate or postgraduate studies. Whilst most of the latest research methods textbooks advise how to do a literature search, very few cover the literature review. This paper covers two types of review: a critical literature review and a systematic review. [ABSTRACT FROM AUTHOR]
• Conducting a Literature Review Authors: Rowley,Jennifer; Slack,Frances Journal: Management Research News Pub Date: 2004 Volume: 27 Issue: 6 Pages:31-39 more... less... Abstract: This article offers support and guidance for students undertaking a literature review as part of their dissertation during an undergraduate or Masters course. A literature review is a summary of a subject field that supports the identification of specific research questions. A literature review needs to draw on and evaluate a range of different types of sources including academic and professional journal articles, books, and web-based resources. The literature search helps in the identification and location of relevant documents and other sources. Search engines can be used to search web resources and bibliographic databases. Conceptual frameworks can be a useful tool in developing an understanding of a subject area. Creating the literature review involves the stages of: scanning, making notes, structuring the literature review, writing the literature review, and building a bibliography.

Some Books from the WU Catalog

• The SAGE handbook of visual research methods [electronic resource] by Edited by Luc Pauwels and Dawn Mannay. ISBN: 9781526417015 Publication Date: SAGE Publications, Inc., 2020.

Helpful Websites

• "How to do a Literature Review" from Ferdinand D. Bluford Library
• "The Literature Review: A Few Tips on Conducting It." from the University of Toronto
• << Previous: Creating an Abstract
• Next: Creating a Poster >>
• Last Updated: Apr 30, 2024 3:17 PM
• URL: https://libguides.wustl.edu/our

Literature Reviews

• What Is It?
• Finding Literature Reviews

A literature review is both a process and a product. As a process, it involves searching for information related to your topic, to familiarize yourself with the relevant research and to identify issues and gaps in the research. In most cases you're seeking to identify the key authors and key arguments that are relevant to your topic, not to exhaustively read everything written on the subject. 

Types of Literature Reviews

A stand alone literature review can be a single work in its own right.  Examples include:

• A class assignment
• A review article

Literature reviews can also be component parts of larger bodies of work. Examples include:

• A thesis / dissertation
• An academic journal article introduction

What is a Literature Review?

A literature review is the writing process of summarizing, synthesizing and/or critiquing the literature found as a result of a literature search. It may be used as background or context for a primary research project.

There are several reasons to review the literature :

• Identify the developments in the field of study
• Learn about the information sources and the research methodologies
• Find gaps in the literature that can become research questions
• Validate the originality of a research project
• Evaluate the methods
• Identify errors to avoid
• Highlight the strengths, weaknesses and controversies in the field of study
• Identify the subject experts

When writing your review, there are objectives you should keep in mind :

• Inform the audience of the developments in the field
• Establish your credibility
• Discuss the relevance and significance of your question(s)
• Provide the context for your methodological approach
• Discuss the relevance and appropriateness of your approach.

​The level of detail or comprehensiveness of your literature review may depend on many things, but especially the purpose and audience of your review. For example, if you're writing a literature review that will aid you in writing a thesis or dissertation, you may want to have a very comprehensive lit review that reviews all relevant literature on a topic, as well as relevant sources beyond what is immediately and freely available (e.g. foundational scholarly articles not available through library collections).

Purpose of a Literature Review

Watch this YouTube video to understand the purpose of a literature review.

• Next: Finding Literature Reviews >>
• Last Updated: Dec 12, 2023 3:07 PM
• URL: https://library.knox.edu/literature-review

• Student Services
• Faculty Services

Literature Reviews - An Introduction: Definition

• How do I recognize a Literature Review?
• How do I find a Literature Review?
• How do I write a Literature Review?

For Library Updates

Literature review: definition and example.

A Literature Review is "a systematic, explicit, and reproducible method for identifying, evaluating, and synthesizing the existing body of completed and recorded work produced by researchers, scholars, and practitioners."

 - From Conducting Research Literature Reviews: From Internet to Paper , by Arlene Fink, 2nd ed. Sage Publications: Thousand Oaks, 2005.

Subject Guide

• Next: How do I recognize a Literature Review? >>
• Last Updated: Dec 11, 2019 3:02 PM
• URL: https://suffolk.libguides.com/LitReview

What Is A Literature Review?

A plain-language explainer (with examples).

By:  Derek Jansen (MBA) & Kerryn Warren (PhD) | June 2020 (Updated May 2023)

If you’re faced with writing a dissertation or thesis, chances are you’ve encountered the term “literature review” . If you’re on this page, you’re probably not 100% what the literature review is all about. The good news is that you’ve come to the right place.

Literature Review 101

• What (exactly) is a literature review
• What’s the purpose of the literature review chapter
• How to find high-quality resources
• How to structure your literature review chapter
• Example of an actual literature review

What is a literature review?

The word “literature review” can refer to two related things that are part of the broader literature review process. The first is the task of  reviewing the literature  – i.e. sourcing and reading through the existing research relating to your research topic. The second is the  actual chapter  that you write up in your dissertation, thesis or research project. Let’s look at each of them:

Reviewing the literature

The first step of any literature review is to hunt down and  read through the existing research  that’s relevant to your research topic. To do this, you’ll use a combination of tools (we’ll discuss some of these later) to find journal articles, books, ebooks, research reports, dissertations, theses and any other credible sources of information that relate to your topic. You’ll then  summarise and catalogue these  for easy reference when you write up your literature review chapter. 

The literature review chapter

The second step of the literature review is to write the actual literature review chapter (this is usually the second chapter in a typical dissertation or thesis structure ). At the simplest level, the literature review chapter is an  overview of the key literature  that’s relevant to your research topic. This chapter should provide a smooth-flowing discussion of what research has already been done, what is known, what is unknown and what is contested in relation to your research topic. So, you can think of it as an  integrated review of the state of knowledge  around your research topic. 

What’s the purpose of a literature review?

The literature review chapter has a few important functions within your dissertation, thesis or research project. Let’s take a look at these:

Purpose #1 – Demonstrate your topic knowledge

The first function of the literature review chapter is, quite simply, to show the reader (or marker) that you  know what you’re talking about . In other words, a good literature review chapter demonstrates that you’ve read the relevant existing research and understand what’s going on – who’s said what, what’s agreed upon, disagreed upon and so on. This needs to be  more than just a summary  of who said what – it needs to integrate the existing research to  show how it all fits together  and what’s missing (which leads us to purpose #2, next). 

Purpose #2 – Reveal the research gap that you’ll fill

The second function of the literature review chapter is to  show what’s currently missing  from the existing research, to lay the foundation for your own research topic. In other words, your literature review chapter needs to show that there are currently “missing pieces” in terms of the bigger puzzle, and that  your study will fill one of those research gaps . By doing this, you are showing that your research topic is original and will help contribute to the body of knowledge. In other words, the literature review helps justify your research topic.  

Purpose #3 – Lay the foundation for your conceptual framework

The third function of the literature review is to form the  basis for a conceptual framework . Not every research topic will necessarily have a conceptual framework, but if your topic does require one, it needs to be rooted in your literature review. 

For example, let’s say your research aims to identify the drivers of a certain outcome – the factors which contribute to burnout in office workers. In this case, you’d likely develop a conceptual framework which details the potential factors (e.g. long hours, excessive stress, etc), as well as the outcome (burnout). Those factors would need to emerge from the literature review chapter – they can’t just come from your gut! 

So, in this case, the literature review chapter would uncover each of the potential factors (based on previous studies about burnout), which would then be modelled into a framework. 

Purpose #4 – To inform your methodology

The fourth function of the literature review is to  inform the choice of methodology  for your own research. As we’ve  discussed on the Grad Coach blog , your choice of methodology will be heavily influenced by your research aims, objectives and questions . Given that you’ll be reviewing studies covering a topic close to yours, it makes sense that you could learn a lot from their (well-considered) methodologies.

So, when you’re reviewing the literature, you’ll need to  pay close attention to the research design , methodology and methods used in similar studies, and use these to inform your methodology. Quite often, you’ll be able to  “borrow” from previous studies . This is especially true for quantitative studies , as you can use previously tried and tested measures and scales. 

How do I find articles for my literature review?

Finding quality journal articles is essential to crafting a rock-solid literature review. As you probably already know, not all research is created equally, and so you need to make sure that your literature review is  built on credible research . 

We could write an entire post on how to find quality literature (actually, we have ), but a good starting point is Google Scholar . Google Scholar is essentially the academic equivalent of Google, using Google’s powerful search capabilities to find relevant journal articles and reports. It certainly doesn’t cover every possible resource, but it’s a very useful way to get started on your literature review journey, as it will very quickly give you a good indication of what the  most popular pieces of research  are in your field.

One downside of Google Scholar is that it’s merely a search engine – that is, it lists the articles, but oftentimes  it doesn’t host the articles . So you’ll often hit a paywall when clicking through to journal websites. 

Thankfully, your university should provide you with access to their library, so you can find the article titles using Google Scholar and then search for them by name in your university’s online library. Your university may also provide you with access to  ResearchGate , which is another great source for existing research. 

Remember, the correct search keywords will be super important to get the right information from the start. So, pay close attention to the keywords used in the journal articles you read and use those keywords to search for more articles. If you can’t find a spoon in the kitchen, you haven’t looked in the right drawer. 

Need a helping hand?

How should I structure my literature review?

Unfortunately, there’s no generic universal answer for this one. The structure of your literature review will depend largely on your topic area and your research aims and objectives.

You could potentially structure your literature review chapter according to theme, group, variables , chronologically or per concepts in your field of research. We explain the main approaches to structuring your literature review here . You can also download a copy of our free literature review template to help you establish an initial structure.

In general, it’s also a good idea to start wide (i.e. the big-picture-level) and then narrow down, ending your literature review close to your research questions . However, there’s no universal one “right way” to structure your literature review. The most important thing is not to discuss your sources one after the other like a list – as we touched on earlier, your literature review needs to synthesise the research , not summarise it .

Ultimately, you need to craft your literature review so that it conveys the most important information effectively – it needs to tell a logical story in a digestible way. It’s no use starting off with highly technical terms and then only explaining what these terms mean later. Always assume your reader is not a subject matter expert and hold their hand through a journe y of the literature while keeping the functions of the literature review chapter (which we discussed earlier) front of mind.

Example of a literature review

In the video below, we walk you through a high-quality literature review from a dissertation that earned full distinction. This will give you a clearer view of what a strong literature review looks like in practice and hopefully provide some inspiration for your own. 

Wrapping Up

In this post, we’ve (hopefully) answered the question, “ what is a literature review? “. We’ve also considered the purpose and functions of the literature review, as well as how to find literature and how to structure the literature review chapter. If you’re keen to learn more, check out the literature review section of the Grad Coach blog , as well as our detailed video post covering how to write a literature review . 

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 .

You Might Also Like:

16 Comments

Thanks for this review. It narrates what’s not been taught as tutors are always in a early to finish their classes.

Thanks for the kind words, Becky. Good luck with your literature review 🙂

This website is amazing, it really helps break everything down. Thank you, I would have been lost without it.

This is review is amazing. I benefited from it a lot and hope others visiting this website will benefit too.

Timothy T. Chol [email protected]

Thank you very much for the guiding in literature review I learn and benefited a lot this make my journey smooth I’ll recommend this site to my friends

This was so useful. Thank you so much.

Hi, Concept was explained nicely by both of you. Thanks a lot for sharing it. It will surely help research scholars to start their Research Journey.

The review is really helpful to me especially during this period of covid-19 pandemic when most universities in my country only offer online classes. Great stuff

Great Brief Explanation, thanks

So helpful to me as a student

GradCoach is a fantastic site with brilliant and modern minds behind it.. I spent weeks decoding the substantial academic Jargon and grounding my initial steps on the research process, which could be shortened to a couple of days through the Gradcoach. Thanks again!

This is an amazing talk. I paved way for myself as a researcher. Thank you GradCoach!

Well-presented overview of the literature!

This was brilliant. So clear. Thank you

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

Chaos to Clarity: Structuring Your Literature Review Format

Master literature review format! Learn key sections, effective citation & analysis tips to write a strong academic review.

Ever wondered how to dive into a mountain of books and articles and come up with something that not just makes sense but shines new light on a topic? What if there was a way to neatly tie together all that information, spot what’s missing, and maybe even pave the way for discoveries? 

That’s what you are going to learn in this article, literature reviews—a place where chaos meets order, and where your insights could set the stage for the next big thing. Let’s break down the literature review format , your essential guide to properly writing a literature review.

Dissecting Literature Review Format 

There are 6 main sections to make a note of while writing a literature review. Those are:

The Introduction Section

Topic background, conceptual framework.

• Synthesis and Evaluation in Literature Reviews
• Conclusion for Your Literature Review
• Reference List in Your Literature Review

Also Read: Essential Components of a Literature Review

The introduction of your literature review is where you set the stage for the entire document. It’s your first opportunity to engage your readers and provide a clear blueprint of what your review will cover and why it matters. This section does more than merely introduce the topic; it establishes the context, defines the scope, and outlines the purpose and objectives of your literature review.

Things to keep in mind while writing an introduction:

• Craft a compelling opening
• Establish the Context and Justification
• Define the Scope and Objectives
• Lay out the Structure
• Give an overview of the Structure

The “Topic Background” section of a literature review serves as the cornerstone for understanding the evolution and current state of the subject matter. It is divided into two crucial sub-sections: Historical Context and Current State of the Topic . 

Delving into these areas provides you with a comprehensive backdrop against which the literature review is framed, enriching the reader’s understanding of why the topic is of interest and what has influenced its development to the current state.

Historical Context

The Historical Context is fundamental in setting the stage for the entire literature review. This section is not just a chronology of events or developments; it’s a curated narrative that highlights the key milestones and turning points that have significantly impacted the topic. 

By examining the historical evolution, the review establishes a timeline of how understanding and perspectives have shifted over the years.

Summary Of Key Historical Developments

This involves identifying and summarizing the major breakthroughs, shifts in thinking, or seminal works that have shaped the topic. It’s important to focus on developments that have a direct relevance to the current understanding and state of the subject. For example, if the topic is about the evolution of renewable energy technologies, this part would outline the initial discovery and use of renewable sources, significant technological innovations, and pivotal policy decisions that have influenced the field.

Relevance Of Historical Context To The Topic

After outlining the key historical developments, it’s crucial to connect these events to the present topic. This means discussing how past events have laid the groundwork for current theories, practices, or debates within the field. It involves analyzing the impact of historical milestones on the subject matter, and explaining how they have contributed to current knowledge, challenges, and research questions. This section makes it clear why understanding history is essential for anyone researching or studying the topic today.

Current State Of The Topic

Moving from the historical context, the review transitions to the present with the Current State of the Topic. This part assesses the latest research, trends, debates, and technological advancements that define the subject area at the moment.

Current Trends Or Updates

Here, the focus shifts to what is happening in the field right now. This could include recent research findings, emerging theories, new methodologies, or the latest technological innovations. The aim is to provide a snapshot of the current research landscape, identifying what themes, questions, or problems are being actively explored. For instance, in the context of digital marketing, this might involve discussing the rise of artificial intelligence in customer relationship management or the impact of social media trends on marketing strategies.

Impact Of These Trends On The Subject Matter

The final step is to assess the implications of these current trends for the topic. This includes considering how recent developments have advanced the field, the challenges they present, and the opportunities they open up for future research. It’s about connecting the dots between what’s happening now and what it means for the subject area moving forward. This not only helps to frame the research questions that the literature review will address but also sets the stage for identifying gaps in the current knowledge, thereby guiding the direction of future studies.

Also Read: What is a literature review? Get the concept and start using it

When doing a literature review, it’s essential to lay a solid foundation for your exploration through a well-defined conceptual framework. This framework acts as a compass, guiding your review’s direction by establishing the key concepts, theories, and perspectives that underpin your topic. 

Definitions And Descriptions

Before diving into the depths of your literature review, it’s crucial to start with the basics. This means clearly identifying and defining the key concepts related to your topic. Think of this as setting the stage for your readers, ensuring they have a clear understanding of the fundamental terms and ideas you will be exploring.

Key Concepts Related To The Topic

Begin by listing the essential concepts central to your review. These are the building blocks of your topic, the terms that will repeatedly appear throughout your exploration. 

Detailed Definitions And Their Relevance

Once you’ve identified these concepts, provide precise and comprehensive definitions for each. Don’t hesitate to explore different dimensions or interpretations of these terms, as this can enrich your readers’ understanding. More importantly, discuss why these concepts are crucial to your review. How do they shape the scope of your exploration? How do they relate to each other and to the broader topic? This step ensures that your readers are not just familiar with the terms but also understand their significance within your review’s context.

Theoretical Perspectives

With the key concepts clearly defined, it’s time to frame your literature review within relevant theoretical perspectives. This is where you align your exploration with existing theories, models, or frameworks that provide insights into your topic.

Important Theories Related To The Topic

Identify the theories that are foundational to your topic. These could range from well-established theories that have long guided research in your field to more contemporary models that offer new insights. For example, a review of organizational behavior might draw on theories of motivation, leadership styles, and organizational culture.

Evaluation Of These Theories And Their Influence On The Topic

After pinpointing the relevant theories, critically assess their contributions to the topic. Consider questions like: How have these theories shaped understanding of the topic? What insights do they offer, and where do they fall short? Are there controversies or debates surrounding these theories? This evaluation not only deepens your review’s analytical depth but also positions your work within the larger academic conversation.

Synthesis And Evaluation In Literature Reviews

The “Synthesis and Evaluation” section is where your literature review truly comes to life. Here, you’re not just summarizing what others have said; you’re weaving together diverse strands of research to present a cohesive picture of the topic at hand.

Comparison And Contrast Of Sources

Synthesizing the literature involves more than listing findings from various studies; it’s about drawing connections between them, highlighting areas of agreement and dispute, and weaving these into a narrative that adds depth and breadth to your understanding of the topic.

Comparative Analysis

Start by grouping your sources based on similarities in their findings, methodologies, or theoretical approaches. This clustering will help you identify trends and common themes across the literature. For example, if several studies have found similar outcomes under comparable conditions, these findings can be grouped to strengthen a particular argument or observation about the topic.

Contrasts Or Conflicts Among Sources

Equally important is the identification of discrepancies in the literature. Do some studies present findings that directly contradict others? Are there differences in how researchers have interpreted similar data? Highlighting these conflicts is crucial, as it can indicate areas where the topic is still evolving or where further research is needed. It also shows your ability to critically engage with the material, a hallmark of scholarly rigor.

Analysis Of Gaps In Literature

One of your primary tasks in the synthesis and evaluation section is to identify what’s missing in the current body of research. This requires a critical eye and a deep understanding of both your topic and the broader field in which it resides.

Identification Of Research Gaps

As you comb through the literature, ask yourself: What questions remain unanswered? Are there underexplored areas or populations? Perhaps certain methodologies have been overlooked, or theoretical perspectives have not been considered. Pinpointing these gaps is not a mere exercise in academic critique; it’s a vital step in advancing knowledge within the field.

Implications Of These Gaps For Future Research

Highlighting gaps in the literature sets the stage for future studies. It’s where you, as the reviewer, can suggest new research directions that could fill these voids or further explore the topic. Discussing the implications of these gaps not only enriches your review but also contributes to the ongoing scholarly conversation. 

Conclusion For Your Literature Review

The conclusion of your literature review is where you bring together all the strands of your argument, synthesizing the insights gained and highlighting the significance of your findings. It’s not just a summary of what has been discussed; it’s an opportunity to underscore the relevance of the review, reflect on the broader implications of your synthesis and evaluation, and suggest directions for future research. 

Summary Of Key Points

Start your conclusion by succinctly summarizing the main points and findings of your review. This isn’t about rehashing every detail but rather about distilling the essence of your exploration. Highlight the critical trends, themes, and conflicts you’ve uncovered, and remind your readers of the significance of these discoveries.

Relevance And Implications Of The Literature For The Topic

Next, focus on the relevance and implications of your findings. This involves stepping back to consider the bigger picture—how does your literature review contribute to the understanding of your topic? Discuss the impact of the trends and gaps you’ve identified on the field, and elaborate on how your synthesis of the literature advances or enriches existing knowledge.

Reflection On The Research Process

Reflecting on the research process itself can provide valuable insights. Consider discussing the challenges you encountered in navigating the literature, such as dealing with conflicting findings or the scarcity of research on certain aspects of your topic. 

Directions For Future Research

One of the most critical aspects of your conclusion is to suggest directions for future research. Be as precise as possible, whether suggesting new methodologies, theoretical frameworks, or specific topics that warrant deeper investigation.

Final Thoughts

End your conclusion with a strong closing statement that reiterates the value of your literature review. Emphasize the importance of continued research on your topic and the potential it holds for advanced understanding within your field. A compelling conclusion reaffirms the significance of your work, leaving your readers with a clear sense of its contribution and the urgent need for further exploration.

Reference List In Your Literature Review

The Reference List is the backbone of your literature review, providing a comprehensive compilation of all the sources you’ve cited throughout your exploration. It’s not merely a formality but a crucial component that lends credibility and rigor to your work.

Importance Of Accuracy And Consistency

The cornerstone of a reliable Reference List is accuracy and consistency in citation style. Whether you’re adhering to APA , MLA , Chicago , or another academic citation format, it’s vital to apply the rules with precision. This includes correctly formatting author names, publication dates, titles, and publication details. 

Organizing Your References

While different citation styles have their own rules for listing references, organizing them in a way that enhances readability and accessibility is universally beneficial. Alphabetical order by the author’s last name is the most common method, as it allows readers to easily locate sources.

Comprehensive Coverage

Your Reference List should be exhaustive, including every work you’ve cited in your review. This extends beyond journal articles and books to encompass reports, conference papers, online resources, and any other materials that have informed your analysis.

The Value Of Annotations

While not always required, providing brief annotations for key sources can add tremendous value to your Reference List. An annotated bibliography offers a succinct summary of each source’s main arguments, methodologies, and findings, as well as its relevance to your literature review.

Digital Accessibility

In today’s digital age, considering the accessibility of your referenced works can greatly enhance the utility of your Reference List. Whenever possible, include Digital Object Identifiers (DOIs) or stable URLs for online sources, ensuring readers can directly access the materials. 

Also read: What Is A DOI? Exploring The Purpose And Importance

Reflecting On Ethical Scholarship

Finally, your Reference List is a reflection of ethical scholarship. By accurately citing all the sources that have informed your work, you’re honoring the intellectual property of other researchers and upholding the academic community’s standards of integrity and respect. 

Crafting a meticulous Reference List is an essential aspect of your literature review that underscores the credibility, depth, and ethical foundation of your research. By adhering to the principles of accuracy, comprehensiveness, and accessibility, you not only facilitate further inquiry but also pay homage to the collective endeavor of knowledge advancement in your field.

Related Article: Navigating the AMA Citation Format: Best Tips for Referencing

In conclusion, writing a literature review involves meticulous structuring, beginning with an engaging introduction that sets the stage, followed by a detailed exploration of the topic’s background, including its historical context and current state. 

A robust conceptual framework lays the groundwork for analysis, leading to a critical synthesis and evaluation of relevant literature. 

The conclusion ties together the review’s key findings and implications, while the reference list meticulously catalogs all cited works. Mastering each section ensures a comprehensive and insightful review, essential for advancing academic understanding and contributing to scholarly discussions.

Related Article: Preliminary Literature Review: A Guide for Effective Research

Science Figures, Graphical Abstracts, And Infographics For Your Research

Revolutionize your research with infographics from Mind the Graph . From science figures, graphical abstracts to infographics, you can unleash the power of creative visuals with this user-friendly platform and make your research captivating. 

Subscribe to our newsletter

Exclusive high quality content about effective visual communication in science.

Unlock Your Creativity

Create infographics, presentations and other scientifically-accurate designs without hassle — absolutely free for 7 days!

About Sowjanya Pedada

Sowjanya is a passionate writer and an avid reader. She holds MBA in Agribusiness Management and now is working as a content writer. She loves to play with words and hopes to make a difference in the world through her writings. Apart from writing, she is interested in reading fiction novels and doing craftwork. She also loves to travel and explore different cuisines and spend time with her family and friends.

Content tags

• Langson Library
• Science Library
• Grunigen Medical Library
• Law Library
• Connect From Off-Campus
• Accessibility
• Gateway Study Center

Email this link

Systematic reviews & evidence synthesis methods.

• Schedule a Consultation / Meet our Team
• What is Evidence Synthesis?
• Types of Evidence Synthesis
• Evidence Synthesis Across Disciplines
• Finding and Appraising Existing Systematic Reviews
• 0. Preliminary Searching
• 1. Develop a Protocol
• 2. Draft your Research Question
• 3. Select Databases
• 4. Select Grey Literature Sources
• 5. Write a Search Strategy
• 6. Register a Protocol
• 7. Translate Search Strategies
• 8. Citation Management
• 9. Article Screening
• 10. Risk of Bias Assessment
• 11. Data Extraction
• 12. Synthesize, Map, or Describe the Results
• Open Access Evidence Synthesis Resources

About This Guide

This research guide provides an overview of the evidence synthesis process, guidance documents for conducting evidence synthesis projects, and links to resources to help you conduct a comprehensive and systematic search of the scholarly literature. Navigate the guide using the tabs on the left.

"Evidence synthesis" refers to rigorous, well-documented methods of identifying, selecting, and combining results from multiple studies. These projects are conducted by teams and follow specific methodologies to minimize bias and maximize reproducibility. A systematic review is a type of evidence synthesis. We use the term evidence synthesis to better reflect the breadth of methodologies that we support, including systematic reviews, scoping reviews , evidence gap maps, umbrella reviews, meta-analyses and others.

Note: Librarians at UC Irvine Libraries have supported systematic reviews and related methodologies in STEM fields for several years. As our service has evolved, we have added capacity to support these reviews in the Social Sciences as well.

Systematic Review OR Literature Review Conducted Systematically?

There are many types of literature reviews. Before beginning a systematic review, consider whether it is the best type of review for your question, goals, and resources. The table below compares systematic reviews, scoping reviews, and systematized reviews (narrative literature reviews employing some, but not all elements of a systematic review) to help you decide which is best for you. See the Types of Evidence Synthesis page for a more in-depth overview at types of reviews.

• Next: UCI Libraries Evidence Synthesis Service >>
• Last Updated: May 25, 2024 10:49 AM
• URL: https://guides.lib.uci.edu/evidence-synthesis

Off-campus? Please use the Software VPN and choose the group UCIFull to access licensed content. For more information, please Click here

Software VPN is not available for guests, so they may not have access to some content when connecting from off-campus.

Review of Related Literature (RRL)

Ai generator.

The Review of Related Literature (RRL) is a crucial section in research that examines existing studies and publications related to a specific topic. It summarizes and synthesizes previous findings, identifies gaps, and provides context for the current research. RRL ensures the research is grounded in established knowledge, guiding the direction and focus of new studies.

What Is Review of Related Literature (RRL)?

The Review of Related Literature (RRL) is a detailed analysis of existing research relevant to a specific topic. It evaluates, synthesizes, and summarizes previous studies to identify trends, gaps, and conflicts in the literature. RRL provides a foundation for new research, ensuring it builds on established knowledge and addresses existing gaps.

Format of Review of Related Literature (RRL)

The Review of Related Literature (RRL) is a critical part of any research paper or thesis . It provides an overview of existing research on your topic and helps to establish the context for your study. Here is a typical format for an RRL:

1. Introduction

• Purpose : Explain the purpose of the review and its importance to your research.
• Scope : Define the scope of the literature reviewed, including the time frame, types of sources, and key themes.

2. Theoretical Framework

• Concepts and Theories : Present the main theories and concepts that underpin your research.
• Relevance : Explain how these theories relate to your study.

3. Review of Empirical Studies

• Sub-theme 1 : Summarize key studies, including methodologies, findings, and conclusions.
• Sub-theme 2 : Continue summarizing studies, focusing on different aspects or variables.
• Sub-theme 3 : Include any additional relevant studies.

4. Methodological Review

• Approaches : Discuss the various methodologies used in the reviewed studies.
• Strengths and Weaknesses : Highlight the strengths and weaknesses of these methodologies.
• Gaps : Identify gaps in the existing research that your study aims to address.

5. Synthesis and Critique

• Integration : Integrate findings from the reviewed studies to show the current state of knowledge.
• Critique : Critically evaluate the literature, discussing inconsistencies, limitations, and areas for further research.

6. Conclusion

• Summary : Summarize the main findings from the literature review.
• Research Gap : Clearly state the research gap your study will address.
• Contribution : Explain how your study will contribute to the existing body of knowledge.

7. References

• Citation Style : List all the sources cited in your literature review in the appropriate citation style (e.g., APA, MLA, Chicago).

Review of Related Literature (RRL) 1. Introduction This review examines research on social media’s impact on mental health, focusing on anxiety and depression across various demographics over the past ten years. 2. Theoretical Framework Anchored in Social Comparison Theory and Uses and Gratifications Theory, this review explores how individuals’ social media interactions affect their mental health. 3. Review of Empirical Studies Adolescents’ Mental Health Instagram & Body Image : Smith & Johnson (2017) found Instagram use linked to body image issues and lower self-esteem among 500 high school students. Facebook & Anxiety : Brown & Green (2016) showed Facebook use correlated with higher anxiety and depressive symptoms in a longitudinal study of 300 students. Young Adults’ Mental Health Twitter & Stress : Davis & Lee (2018) reported higher stress levels among heavy Twitter users in a survey of 400 university students. LinkedIn & Self-Esteem : Miller & White (2019) found LinkedIn use positively influenced professional self-esteem in 200 young professionals. Adult Mental Health General Social Media Use : Thompson & Evans (2020) found moderate social media use associated with better mental health outcomes, while excessive use correlated with higher anxiety and depression in 1,000 adults. 4. Methodological Review Studies used cross-sectional surveys, longitudinal designs, and mixed methods. Cross-sectional surveys provided large data sets but couldn’t infer causation. Longitudinal studies offered insights into long-term effects but were resource-intensive. Mixed methods enriched data through qualitative insights but required careful integration. 5. Synthesis and Critique The literature shows a complex relationship between social media and mental health, with platform-specific and demographic-specific effects. However, reliance on self-reported data introduces bias, and many cross-sectional studies limit causal inference. More longitudinal and experimental research is needed. 6. Conclusion Current research offers insights into social media’s mental health impact but leaves gaps, particularly regarding long-term effects and causation. This study aims to address these gaps through comprehensive longitudinal analysis. 7. References Brown, A., & Green, K. (2016). Facebook Use and Anxiety Among High School Students . Psychology in the Schools, 53(3), 257-264. Davis, R., & Lee, S. (2018). Twitter and Psychological Stress: A Study of University Students . Journal of College Student Development, 59(2), 120-135. Miller, P., & White, H. (2019). LinkedIn and Its Effect on Professional Self-Esteem . Journal of Applied Psychology, 104(1), 78-90. Smith, J., & Johnson, L. (2017). The Impact of Instagram on Teen Body Image . Journal of Adolescent Health, 60(5), 555-560. Thompson, M., & Evans, D. (2020). The Relationship Between Social Media Use and Mental Health in Adults . Cyberpsychology, Behavior, and Social Networking, 23(4), 201-208.

Review of Related Literature (RRL) Examples

Review of related literature in research, review of related literature in research paper, review of related literature qualitative research.

Review of Related Literature Quantitative Research

More Review of Related Literature (RRL) Examples

• Impact of E-learning on Student Performance
• Effectiveness of Mindfulness in Workplace
• Green Building and Energy Efficiency
• Impact of Technology on Healthcare Delivery
• Effects of Nutrition on Cognitive Development in Children
• Impact of Employee Training Programs on Productivity
• Effects of Climate Change on Biodiversity
• Impact of Parental Involvement on Student Achievement
• Effects of Mobile Learning on Student Engagement
• Effects of Urban Green Spaces on Mental Health

Purpose of the Review of Related Literature (RRL)

The Review of Related Literature (RRL) serves several critical purposes in research:

• Establishing Context : It situates your research within the broader field, showing how your study relates to existing work.
• Identifying Gaps : It highlights gaps, inconsistencies, and areas needing further exploration in current knowledge, providing a clear rationale for your study.
• Avoiding Duplication : By reviewing what has already been done, it helps ensure your research is original and not a repetition of existing studies.
• Building on Existing Knowledge : It allows you to build on the findings of previous research, using established theories and methodologies to inform your work.
• Theoretical Foundation : It provides a theoretical basis for your research, grounding it in existing concepts and theories.
• Methodological Insights : It offers insights into the methods and approaches used in similar studies, helping you choose the most appropriate methods for your research.
• Establishing Credibility : It demonstrates your familiarity with the field, showing that you are well-informed and have a solid foundation for your research.
• Supporting Arguments : It provides evidence and support for your research questions, hypotheses, and objectives, strengthening the overall argument of your study.

How to Write Review of Related Literature (RRL)

Writing a Review of Related Literature (RRL) involves several key steps. Here’s a step-by-step guide:

1. Define the Scope and Objectives

• Determine the Scope : Decide on the breadth of the literature you will review, including specific themes, time frame, and types of sources.
• Set Objectives : Clearly define the purpose of the review. What do you aim to achieve? Identify gaps, establish context, or build on existing knowledge.

2. Search for Relevant Literature

• Identify Keywords : Use keywords and phrases related to your research topic.
• Use Databases : Search academic databases like Google Scholar, PubMed, JSTOR, etc., for relevant articles, books, and papers.
• Select Sources : Choose sources that are credible, recent, and relevant to your research.

3. Evaluate and Select the Literature

• Read Abstracts and Summaries : Quickly determine the relevance of each source.
• Assess Quality : Consider the methodology, credibility of the authors, and publication source.
• Select Key Studies : Choose studies that are most relevant to your research questions and objectives.

4. Organize the Literature

• Thematic Organization : Group studies by themes or topics.
• Chronological Organization : Arrange studies in the order they were published to show the development of ideas over time.
• Methodological Organization : Categorize studies by the methods they used.

5. Write the Review

• State the purpose and scope of the review.
• Explain the importance of the topic.
• Theoretical Framework : Present and discuss the main theories and concepts.
• Summarize key studies, including their methodologies, findings, and conclusions.
• Organize by themes or other chosen organizational methods.
• Methodological Review : Discuss the various methodologies used, highlighting their strengths and weaknesses.
• Synthesis and Critique : Integrate findings, critically evaluate the literature, and identify gaps or inconsistencies.
• Summarize the main findings from the literature review.
• Highlight the research gaps your study will address.
• State how your research will contribute to the existing knowledge.

6. Cite the Sources

• Use Appropriate Citation Style : Follow the required citation style (e.g., APA, MLA, Chicago).
• List References : Provide a complete list of all sources cited in your review.

What is an RRL?

An RRL summarizes and synthesizes existing research on a specific topic to identify gaps and guide future studies.

Why is RRL important?

It provides context, highlights gaps, and ensures new research builds on existing knowledge.

How do you write an RRL?

Organize by themes, summarize studies, evaluate methodologies, identify gaps, and conclude with relevance to current research.

What sources are used in RRL?

Peer-reviewed journals, books, conference papers, and credible online resources.

How long should an RRL be?

Length varies; typically 10-20% of the total research paper.

What are common RRL mistakes?

Lack of organization, insufficient synthesis, over-reliance on outdated sources, and failure to identify gaps.

Can an RRL include non-scholarly sources?

Primarily scholarly, but reputable non-scholarly sources can be included for context.

What is the difference between RRL and bibliography?

RRL synthesizes and analyzes the literature, while a bibliography lists sources.

How often should an RRL be updated?

Regularly, especially when new relevant research is published.

Can an RRL influence research direction?

Yes, it identifies gaps and trends that shape the focus and methodology of new research.

Text prompt

• Instructive
• Professional

10 Examples of Public speaking

20 Examples of Gas lighting

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

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List
• v.9(4); 2023
• PMC10632935

Original research

Heterogeneity of determining disease severity, clinical course and outcomes in systemic sclerosis-associated interstitial lung disease: a systematic literature review, liubov petelytska.

1 Rheumatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland

2 Department Internal Medicine #3, Bogomolets National Medical University, Kiiv, Ukraine

Francesco Bonomi

3 Department of Experimental and Clinical Medicine, Division of Rheumatology, University of Florence - Careggi University Hospital, Florence, Italy

Carlo Cannistrà

Elisa fiorentini, silvia peretti, sara torracchi, pamela bernardini, carmela coccia, riccardo de luca, alessio economou, juela levani, marco matucci-cerinic.

4 Unit of Immunology, Rheumatology, Allergy and Rare Diseases, San Raffaele Hospital, Milan, Italy

Oliver Distler

Cosimo bruni, associated data.

rmdopen-2023-003426supp001.pdf

Data are available upon reasonable request. All data will be made available upon reasonable request to the corresponding author.

Objective The course of systemic sclerosis-associated interstitial lung disease (SSc-ILD) is highly variable and different from continuously progressive idiopathic pulmonary fibrosis (IPF). Most proposed definitions of progressive pulmonary fibrosis or SSc-ILD severity are based on the research data from patients with IPF and are not validated for patients with SSc-ILD. Our study aimed to gather the current evidence for severity, progression and outcomes of SSc-ILD.

Methods A systematic literature review to search for definitions of severity, progression and outcomes recorded for SSc-ILD was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines in Medline, Embase, Web of Science and Cochrane Library up to 1 August 2023.

Results A total of 9054 papers were reviewed and 342 were finally included. The most frequent tools used for the definition of SSc-ILD progression and severity were combined changes of carbon monoxide diffusing capacity (DLCO) and forced vital capacity (FVC), isolated FVC or DLCO changes, high-resolution CT (HRCT) extension and composite algorithms including pulmonary function test, clinical signs and HRCT data. Mortality was the most frequently reported long-term event, both from all causes or ILD related.

Conclusions The studies presenting definitions of SSc-ILD ‘progression’, ‘severity’ and ‘outcome’ show a large heterogeneity. These results emphasise the need for developing a standardised, consensus definition of severe SSc-ILD, to link a disease specific definition of progression as a surrogate outcome for clinical trials and clinical practice.

PROSPERO registration number CRD42022379254.Cite Now

WHAT IS ALREADY KNOWN ON THIS TOPIC

• Progression of interstitial lung disease (ILD) is associated with the poorer outcome in systemic sclerosis (SSc).
• Established and validated criteria of progressive and severe SSc-ILD are required to drive monitoring and intensification of treatment strategy.
• Most proposed definitions are derived from idiopathic pulmonary fibrosis and are not fully validated for patients with SSc-ILD.

WHAT THIS STUDY ADDS

• This systematic literature review summaries the current data of different definitions used in clinical trials and observational studies.
• The large heterogeneity of presented definitions emphasises the need to develop standardised, consensus definitions.
• Patients’ perspective need also to be taken into account, in particular when defining disease-related outcomes.

HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY

• The definition of progression should be the surrogate outcome for long-term severe events, meaningful for both patients and physicians.
• Our data are the basis to create a disease-specific definition of progression of SSc-associated interstitial lung disease.
• This will further allow the identification of a patient phenotype at higher risk of progression, as possible candidate for treatment intensification.

Introduction

Systemic sclerosis (SSc) is a rare autoimmune disease characterised by tissue inflammation and vasculopathy, leading to skin and internal organs fibrosis. 1 2 Mortality related to SSc is the highest among all rheumatic diseases, 3 and the 10-year survival rate of patients with SSc is 65%–73% in Europe and 54%–82% in North America. 4 Interstitial lung disease (ILD) is a prominent feature of SSc and is the leading cause of death according to 'European League Against Rheumatism (EULAR) Scleroderma Trials and Research (EUSTAR) cohort data. 3 5 Nearly 50% of patients with SSc develop ILD during the disease course, with the higher risk in early phases, in particular for the diffuse cutaneous subset (dcSSc). 6 7 Although the high-resolution CT (HRCT) of the chest is the gold standard imaging technique for ILD assessment, pulmonary function tests (PFTs) and clinical assessment of respiratory symptoms also play a significant role in the management of patients with SSc-ILD. Half of the patients with SSc have confirmed ILD on first chest HRCT assessment. 8 Restrictive patterns on PFTs with reduced forced vital capacity (FVC) and diffusion capacity of the lung for carbon monoxide (DLCO) are detected more rarely. 9

At SSc diagnosis, screening for ILD is recommended in every patient with SSc based on expert evidence-based European and American consensus documents. 10 11 Despite this, still too many physicians tend to perform diagnostic HRCTs only when patients develop respiratory symptoms or to screen only in patients at higher risk (eg, dcSSc, positive for Scl-70 antibodies, African-American ethnicity, high modified Rodnan skin score (mRSS)). 12–17

Compared with the progressive fibrosing disease course of idiopathic pulmonary fibrosis (IPF), the course of SSc-ILD may be highly heterogeneous, 18 with stable and progressive periods. A recent EUSTAR database analysis showed that 67% of all patients with SSc-ILD may experience progression at any time over an average follow-up of 5 years, with most patients with progressive ILD showing a rather slow lung function deterioration afterwards or even no episode of further major decline. 19

Currently, no established consensus is available on the definition of SSc-ILD progression among experts and in the literature. In observational studies and clinical trials, the most used definition of ILD progression is a ≥10% relative decline in FVC. 20–29 An FVC relative decline ≥10% is a strong predictor of reduced survival in patients with SSc-ILD. 29 Some studies prefer to use the CT fibrosis extent as a marker of ILD progression. 30–32 The recent 2022 American Thoracic Society (ATS)/ European Respiratory Society (ERS)/ Japanese Respiratory Society (JRS)/ Latin American Thoracic Association (ALAT) Clinical Practice Guideline on Progressive Fibrosing ILDs defined progressive pulmonary fibrosis on the basis of the presence of at least two of the following three criteria occurring within 1 year: worsening respiratory symptoms, physiological evidence of disease progression (absolute decline in FVC of at least 5% predicted or/and absolute decline in DLCO at least 10% predicted) and radiological evidence of disease progression. 33 Taking into account differences between SSc-ILD and IPF, post-hoc analysis of the Scleroderma Lung Study (SLS) I and II indicated a decline in FVC of 3.0% as the minimal change for a clinically important difference. 34

The objective of this systematic literature review (SLR) is to collect the available scientific evidence about definitions of severity, progression and outcomes in SSc-ILD. The final aim is to inform the creation process of the definition of ‘long-term severe SSc-ILD’. This long-term outcome will then be linked to a definition of ILD progression specific for SSc, as surrogate outcome, to help guiding decisions for management and monitoring disease course for patients diagnosed with SSc-ILD.

Materials and methods

A systematic search of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify papers that include definitions of SSc-ILD severity, progression and outcome (PROSPERO registration number CRD42022379254). We considered outcomes as events that were recorded during a study and had impact on the patients’ health and could be related to ILD. These were different from measurements and definitions of progression, which was only related to ILD and therefore recorded separately.

In summary, Medline, Embase, Web of Science databases and Cochrane Library were searched up to 1 August 2023. A single author (CB) with established experience 35–37 performed the literature search using the search, strings detailed in online supplemental file 1 .

Supplementary data

The citations retrieved from these databases were entered in the software EndNote V.20 and duplicates were removed. The citations were evaluated in a two-step process by teams of two independent evaluators (LP, FB, CC, EF, SP, ST, PB, CC, RDL, AE, JL), including title/abstract evaluation (step 1) and full-text evaluation (step 2). Discrepancies were resolved by direct discussion between the two assessors, otherwise through the opinion of a third evaluator (CB). Randomised clinical trials (RCT), cross sectional or longitudinal studies (both retrospective or prospective) were included in the SLR if they were focused on SSc or on cohorts in which data on patients with SSc could be extracted, considered ILD as primary target (representing at least one of population, exposure, outcome) and included at least 10 adult patients. Exclusion criteria were papers written in languages other than English, non-clinical studies, lung involvement due to other causes (ie, other diseases, smoking or professional exposure, etc), ILD onset as an outcome, literature reviews and no full-text availability.

A reproducibility exercise was conducted on the first 20 abstracts for step 1 and the first 5 full texts for step 2 derived from the selection and performed by all extractors, to ensure homogeneity in evaluation and data extraction (90% of agreement achieved).

Out of 9054 papers identified by the primary literature search, 1618 articles were selected for full-text analysis ( figure 1 ). The reasons for exclusion from the first selection step were: wrong population (n=3270), wrong study type (n=4036) and not English article (n=174). Among the remaining 1618 papers evaluated as full text in step 2, 1276 manuscripts were excluded due to no definition of severity/progression/outcome presented (n=818), wrong population (n=232), wrong study type (n=95), full texts not retrieved (n=103) and not English paper (n=26). Finally, 342 manuscripts were extracted in step 3, including 43 939 patients with SSc-ILD, range 6–3778 patients per paper (data available for 305/342 papers). Mean age was 50 years and ranged from 32 to 66 years (data available for 141/342 papers), the median age ranged from 18 to 75 years (data available for 29 papers), 68.6% were women (data available for 161/342 papers). The mean disease duration ranged from 1 to 11 years (data available for 165/342 papers). The design of the study was retrospective in 167 cases (49%), prospective in 122 (37%), RCT in 31 (9%), cross-sectional in 14 (4%), case control in 5 (1%) and case-series in 3 (0.9%). Regarding the SSc classification criteria, 147 studies used the 2013 American College of Rheumatology (ACR)/EULAR criteria, 125 the 1980 ARA criteria, in 20 studies patients meet 2013 ACR/EULAR criteria and 1980 ARA criteria simultaneously, 7 papers used other criteria (including Leroy and others) and 43 did not indicate any criteria.

Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagram of studies selection. ILD, interstitial lung disease; SSc, systemic sclerosis.

The SLR results are summarised below and divided in three sections: definitions of severity, progression and outcomes of SSc-ILD.

Definitions of SSc-ILD severity

A definition of SSc-ILD severity was included in 155 (45%) papers. It was based on HRCT data in 62 (40%) studies, on combined HRCT and FVC changes in 25 (16%), on FVC changes in 27 (17%), on combined FVC and DLCO changes in 15 (10%) and on DLCO changes in 12 (8%). The most used definitions of SSc-ILD severity are given in table 1 , and less frequent are mentioned in online supplemental table 1 .

DLCO, diffusion capacity of the lung for carbon monoxide; FVC, forced vital capacity; HRCT, high-resolution CT; ILD, interstitial lung disease; PFTs, pulmonary function tests.

ILD extent presented as percentage of affected parenchyma on HRCT was the most frequently used imaging parameter (89 studies, 8327 patients), both alone (62 studies, 4974 patients) or in combination with PFT parameters (27 papers, 3353 patients). Different cut-off points were proposed, ranging from >10% to >50%: the most frequent cutoff was >20% as proposed by the visual Goh et al staging system on five levels, 38 which was presented in 24 studies including 2031 patients. According to the modified Goh et al scoring system, extensive disease was defined as lung involvement>20% on HRCT or 10%–30% ILD involvement on HRCT with FVC<70% predicted. Limited disease was determined as ≤20% ILD involvement on HRCT or 10%–30% lung involvement on HRCT and an FVC≥70% predicted. 38

The second most frequently used HRCT assessment tool of ILD severity was the semiquantitative scoring proposed by Warrick et al , 39 which combines severity and extent of disease. In this score, different abnormalities (ground-glass opacity alone, mixed ground glass and reticular disease, reticular fibrosis alone and honeycombing) correspond to increasingly severe disease and consequently receive increasingly higher scores. The extent is determined based on the total number of bronchopulmonary segments involved for each abnormality, with a maximum score of 31 points. The Warrick score was used in 10 studies, including altogether 519 patients with considered cut-off >15 points (in 3 studies), >10 points (in 1 study) and >7 (in 2 studies).

The other HRCT assessments to present ILD severity were the CT score grade 3 or grade 4 as corresponding to 50%–74% or >75% or lung parenchyma involved (five studies), the predominance of reticular or honeycombing appearance (four studies), extensive-ILD Z score≥3 (two studies), presence of ground glass opacities (one study), presence of linear opacities of >3 mm thickness and presence of honeycombing (one study).

PFTs parameters were used as assessment tools for SSc-ILD severity in 67/155 papers, including altogether 8766 patients (as part of combined indexes in 40 studies) with % predicted FVC as the most frequently used parameter. FVC was used to define severity as a single parameter in 27 papers (5078 patients), in combination with % predicted DLCO in 15 papers (1519 patients) or with other parameters in 25 papers (3287 patients). Among the included studies, a cutoff for FVC<45% was used in 1 paper (246 patients), FVC<50% was used in 27 papers (4026 patients), <60% in 1 paper (20 patients), <70% in 29 papers (5298 patients) and<80% in 2 paper (3867 patients). Per cent predicted DLCO as isolated severity marker of SSc-ILD was presented in 12 studies including 588 patients, with a cutoff <40% (4 papers, 117 patients), <50% (4 papers, 315 patients) or <70% (4 papers, 156 patients).

There were some composite measures for ILD severity in the literature: the ILD—Gender, Age, Physiology index (taking into account the ILD subtype, gender, age, FVC and DLCO), a composed index (including the body mass index, DLCO results, Medical Research Council dyspnoea score (mMRC) and the 6-min walking distance (6MWD)), and the du Bois index. The Medsger severity scale was used in three studies including altogether 63 patients.

The severity of ILD was estimated also according to the clinical symptoms: exercise tolerance/dyspnoea score>1 (1 paper, 57 patients), NYHA functional class III-IV (1 paper, 21 patients), exercise oxygen desaturation (1 paper, 63 patients) and a grade IV on the mMRC (1 paper, 28 patients).

Definitions of SSc-ILD progression

Out of 207 studies including definitions of SSc-ILD progression, 62 (30%) provided a definition referred to combined DLCO and FVC changes, 65 (31%) to isolated FVC changes, 27 (13%) to DLCO changes, 20 (10%) to HRCT extension, 13 (6%) to combination of PFT and HRCT data, 11 (5%) to combination of PFTs, clinical signs and HRCT data, 5 (2%) to vital capacity decline and 4 (2%) to other aspects ( tables 2 and 3 ). The time frame of progression assessment were 6 months (5.3% papers), 12 months (35.3 %), 24 months (18.4% papers), 36 months (7.7%), 60 months (3.4%), more than 60 months (7.7%), other (9.2 %) or unknown (13.0%).

Definitions of SSc-ILD progression based on a single parameter

DLCO, carbon monoxide diffusing capacity; FVC, forced vital capacity; HRCT, high-resolution CT; ILD, interstitial lung disease.

Definitions of SSc-ILD progression based on the combination of multiple parameters

Among PFTs parameters, FVC was the most frequently used in 150/207 manuscripts. Among the included manuscripts, various cutoffs for decline were presented, representing FVC decline over a variable follow-up duration ( tables 2 and 3 and Supplement table 2,3): >20% in 3 papers (96 patients), >15% in 6 papers (390 patients), >10% in 108 papers (14 237 patients), 5%–10% 13 papers (1656 patients), >5% in 14 papers (2075 patients), >3.3% in 4 papers (1418 patients), > 0.08 L per year in 1 paper (29 patients), any decline in 1 paper (148 patients). In addition, progression to FVC<70% at 36 months was recorded in 2 papers (212 patients) and <55% at follow-up in another paper (44 patients). Percent decline of DLCO as marker of SSc-ILD progression was presented in 103 studies including 10 152 patients. Also for DLCO decline, different cutoffs have been proposed over different time points ( tables 2 and 3 and Supplement table 2,3): >30% (1 paper, 34 patients), >20% (2 papers, 53 patients), >15% (69 papers, 8766 patients), >10% (26 papers, 1152 patients), >7% (1 paper, 33 patients), >5% (1 paper, 25 patients), DLCO<70% at longest follow-up (1 paper, 44 patients) and any decline in 1 paper (44 patients).

The most frequently used definition of SSc-ILD progression based on PFT changes were decline FVC>10% or 5%–10% plus DLCO>15% (53 studies, 7553 patients), otherwise as decline FVC>10% or DLCO>10% (14 studies, 825 patients).

Definitions based on HRCT changes included the increase of ILD extent by >5% in 2 paper (102 patients), >10% in 4 papers (358 patients), >20% in 6 papers (308 patients), ≥2% increase in quantitative ILD score 40 in 2 papers (269 patients), ≥4% increase in quantitative ILD score 40 in 1 paper (97 patients), increase in the ILD score proposed by Kazerooni et al 41 ≥ 1 point in 1 paper (73 patients) or ≥2 points in 2 papers (116 patients), otherwise any increase in ILD extent in 6 papers (697 patients). The Kazerooni assessment strategy includes the extent of ground-glass opacity (alveolar score) and honeycombing (interstitial score) on a scale of 0–5 in the three lobes of both lungs as follows: 0—no alveolar disease, 1—ground glass involving <5% of the lobe, 2—ground glass involving up to 25% of the lobe, 3—ground glass involving 25%–49% of the lobe, 4—ground glass involving 50%–75% of the lobe, 5—ground glass involving >75% of the lobe for alveolar score; 0—no interstitial disease, 1—septal thickening without honeycombing, 2—honeycombing involving up to 25% of the lobe, 3—honeycombing involving 25%–49% of the lobe, 4—honeycombing involving 50%–75% of the lobe, 5—honeycombing involving >75% of the lobe for interstitial score. 41 The increasing extent ILD was also part of a composite definition in 9 papers (1196 patients), combined with decline FVC and/or DLCO with deterioration of dyspnoea symptoms.

Finally, progression of ILD was also estimated according to clinical symptoms in 11 papers (944 patients), all using worsening of dyspnoea in combination with PFT or HRCT changes.

Complementary to ILD progression, 16/342 papers presented definitions of SSc-ILD improvement. Generally, the most frequently used definitions were based on PFTs changes: isolate increase of FVC (7 studies, 262 patients) with cutoff of 3.6%, 5%, 10% or 15% (Supplementary Table 4), isolate increase DLCO (2 studies, 45 patients) with cutoff of 10% and 15%, increase FVC or DLCO (5 studies, 123 patients), improvement in VC>10% (1 study, 7 patients) and increase 6MWD>15% (1 study, 7 patients).

Definitions of SSc-ILD outcome

The last part of our study was focused on outcomes in SSc-ILD. Information about outcomes of SSc-ILD was present in 175 articles. The most frequent endpoint was mortality ( table 4 ). According to the SRL results, mortality was categorised to mortality due to ILD (12 studies, 2628 patients), SSc-related mortality (8 studies, 2091 patients), 15-year mortality (2 studies, 628 patients), 10-year mortality (16 studies, 2732 patients), 5-year mortality (22 studies, 4771 patients), 3-year mortality (10 studies, 952 patients), 1-year mortality (13 studies, 947 patients), in-hospital mortality (5 studies, 1899 patients), mortality after lung transplantation (1 study, 72 patients) and overall mortality with follow-up duration from 12 months to 360 months (68 studies, 8076 patients). Other popular recorded outcomes of patients with SSc-ILD were hospitalisation (6 papers, 1835 patients), end-stage ILD (6 paper, 501 patients), lung transplantation (3 papers, 375 patients) and infections (2 papers, 82 patients).

Definitions of outcome in SSc-ILD

ILD, interstitial lung disease; SSc, systemic sclerosis; Unk, unknown/not specified.

Parameters of other SSc-related organ progressions or improvement were also considered as outcomes in 21/175 studies (Supplementary Table 5), such as malignancy, changes in the mRSS, left ventricular ejection fraction, new onset of pulmonary hypertension, new onset of digital ulcers, overall disease progression (defined according to the occurrence of at least one organ progression), compression fractures, femoral head necrosis, newly diagnosed arterial hypertension, newly diagnosed diabetes, hyperlipidaemia requiring treatment, abnormal liver function tests and decrease Health Assessment Questionnaire Disability Index. The duration of patients’ follow-up for outcome assessment ranged from 1 to 30 years.

In more than a half of the patients with SSc, ILD may determine a meaningful impact on quality of life, morbidity and survival. 5 7 Unlike the progressive fibrosing disease course of IPF, the course of SSc-ILD is definitely variable, with phases of rapid or slow disease progression, disease stability or improvement. 19 In fact, ILD progression can be observed not only during the first 3 years of disease duration, but also in later stages. In patients with SSc, a recent analysis from the EUSTAR cohort showed that the frequency of ILD progression is over 10% every year, regardless of disease duration, which ranged from less than 3 to more than 15 years after onset of Raynaud’s phenomenon. 42 The high heterogeneity of the course of SSc-ILD requires appropriate monitoring and approach to treatment strategy.

Although there is no consensus on which definition of SSc-ILD progression best fits the case of a surrogate outcomes, most ILD progression definitions have been related to increased morbidity and mortality. This stresses the need to identify patients at higher risk of progression, to start an early treatment. 43 Overall, there is consensus among SSc-ILD experts that the definition of SSc-ILD progression should cover multiple domain that are usually affected by this complication. 44 The recent 2022 ATS/ERS/JRS/ALAT Clinical Practice Guideline on progressive fibrosing ILD based the definition of ILD progression on at least two of worsening of respiratory symptoms, physiological evidence of disease progression and radiological progression, presenting within a 1–2 years’ time frame. 33 Despite being currently proposed to define a progressive phenotype also in SSc, the current definition has not been tested so far in this disease, and therefore lacks a data-driven support. Similarly, the "Efficacy and safety of Nintedanib in patients with progressive fibrosing interstitial lung disease" (INBUILD) study defined a progressive ILD phenotype as a relative decline in the FVC predicted≥10% or a relative decline in FVC predicted of 5%–10% associated to worsening of respiratory symptoms or an increased extent of fibrosis on HRCT, or worsening of respiratory symptoms. These events could be recorded over a time observation up to 24 months and manifest despite management with standard of care treatments, excluding nintedanib or pirfenidone. 45 However, only a small proportion of SSc-ILD cases were included in this study, which limits the possibility to extrapolate the applicability of this definition to this specific population.

Applying a combined and multidomain definition of progression in the large prospective Canadian Registry for Pulmonary Fibrosis, progression events were recorded in in 49% patients with SSc-ILD within 24 months. Progressive fibrosing-ILD (PF-ILD) was defined as a relative FVC decline ⩾10%, death, lung transplantation or any two of: relative FVC decline ⩾5% and<10%, worsening respiratory symptoms or worsening fibrosis on CT of the chest, all within 24 months from baseline. Based on which definition was used to determine progression, the frequency of events ranged from 8% (relative FVC decline 5%–9% with fibrosis on CT) to 49% (relative FVC decline ⩾10%). 46 However, it should be highlighted that pulmonology registry are likely enriched for progressive, severe patients and reflects daily practice in pulmonology, which is not necessarily representative of the daily clinical practice in rheumatology. Although based only on functional decline, the number of progressive events in EUSTAR cohort are, in fact, much lower. 19 A study from a large European centre by Nasser et al reported that 168 out of 617 patients (27%) met the PF-ILD criteria during a 7-year period. 47 Another retrospective study including nine specialist centres in the UK by Simpson et al identified the new incident cases of PF-ILD rate according to the INBUILD criteria in 14.5% assessed over a 2-year period. 48 Finally, another recent analysis of 826 patients with SSc-ILD from the EUSTAR database showed that 27% patients experienced ILD progression defined as a decline in predicted FVC>5% during any 12-month period, and 67% of all patients with SSc-ILD experienced progression at any time over the mean 5-year follow-up. 19 However, most patients with SSc-ILD (58%) were stable (decline or increase in FVC<5%) or improved (increase in FVC≥5% predicted) during any 12-month period and only 8% showed rapid, continuously declining FVC. 19

Our SLR focuses on definitions of severity, progression and outcome for patients with SSc-ILD, considering the existing literature data until 1 August 2023. As a result of our research, we presented data on 175 articles regarding the SSc-ILD outcomes. The most frequent outcomes were mortality (157 studies), end-stage lung disease (6 studies) and hospitalisation (6 studies). Concerning severity of SSc-ILD, ILD extent on HRCT over 20% of the parenchyma is most frequently used, alone or in combination with PFT parameters. Among PFTs parameters for severity assessment, predicted FVC values <50% or <70% and predicted DLCO values <40%, <50% or <70% were used in most papers. Our review also confirmed the importance of both PFTs (mostly using FVC% predicted and DLCO% predicted), and HRCT as a tool to identify progressive SSc-ILD. Finally, several studies have proposed criteria for progression of SSc-ILD based on a combination of clinical signs (worsening of dyspnoea) in combination with pulmonary function measures and radiographic extent of fibrosis on HRCT.

Independent of the definition used, it is important to detect ILD progression, as it can represent a surrogate outcome for future severe events. 49 Using data from the SLS I and II, the post-hoc analysis by Volkmann et al demonstrated that radiographic progression of SSc-ILD (defined by a≥2% increase in total quantitative ILD score—QILD score) over the course of 1–2 years is associated with an increased risk of long-term mortality. 50 Even after adjusting for other factors known to affect survival in patients with SSc, worsening of ILD on HRCT remained associated with mortality, in particular in the SLS II subgroup. 50 The ability of PFT changes at 1 and 2 years to predict long-term mortality over more than 15 years was estimated in study by Goh et al . 29 The changes in the FVC% predicted in 1 year provided the most accurate prognostic information, with the optimal expression of FVC change consisting of either a ≥10% decline in the FVC from baseline or a 5%–9% decline in the FVC with a ≥15% decline in the DLCO. The prognostic value of PFT trends in the whole cohort was entirely explained by the disease progression in patients with extensive lung fibrosis, defined as ILD affecting more than 20% of the lung parenchyma. The categorical changes in the carbon monoxide transfer coefficient (KCO) and the FVC:DLCO ratio in those with limited lung fibrosis and change in the composite categorical decline (a≥10% decline in the FVC from baseline or a 5%–9% decline in the FVC with a ≥15% decline in the DLCO) in those with extensive lung fibrosis at 2 years were independent prediction factors of mortality. The prognostic value of the PFT changes was further confirmed in a mortality prediction model using data from the SLS I and II trials. 17 The final SLS II survival models demonstrated that older age, higher baseline values of modified Rodnan’s skin score, as well as a more meaningful decline of FVC%-predicted and DLCO%-predicted over 24 months were associated with worse survival. Despite the established value of PFT as a surrogate marker of mortality in SSc-ILD, the EUSTAR study by Hoffmann-Vold AM et al could not identify significant differences in mortality between patients with a≥10% decline in the FVC (12%), decline in FVC 5%–10% predicted (15%) or decline or increase in FVC<5% (9%) over the initial 12-month period. 19

Severe disease and long-term outcomes are the cornerstone of SSc-ILD management, as they represent the target that should be avoided or delayed through medications. The currently available RCTs on SSc-ILD used FVC decline as an outcome due to its good surrogacy for survival [SLS I—percentage of the predicted FVC value at 12 months, SLS II—percentage of the predicted FVC value at 24 months, the "Safety and Efficacy of Nintedanib in Systemic Sclerosis" (SENSCIS) study —the annual rate of absolute decline in FVC assessed over 52 weeks, FaSScinate and FocuSSced trial—percentage of the predicted FVC value at 48 weeks). 26 28 51–53 In comparison to SSc-ILD, the field of RCTs in PAH has moved forward from using pure functional outcomes as primary endpoints, aiming at preventing morbidity and mortality events. For example, the primary outcome in the "study with an ERA in Pulmonary arterial Hypertension to Improve cliNical outcome" (SERAPHIN) trial was the time from the initiation of treatment to the first occurrence of a composite end point of death, or worsening of pulmonary arterial hypertension (defined as events such as atrial septostomy, lung transplantation, initiation of treatment with intravenous or subcutaneous prostanoids). 54 Similarly, the "study of first-line Ambrisentan and Tadalafil combination therapy in subjects with pulmonary arterial hypertension" (AMBITION) trial used the first event of clinical failure as primary endpoint, which was defined as the first occurrence among death, hospitalisation for worsening pulmonary arterial hypertension, disease progression or unsatisfactory long-term clinical response. 55 Therefore, the combination of long-term outcomes and severe disease worsening, including both functional, radiological and clinical events, could help to create a combined morbidity–mortality outcome also for SSc-ILD. This might be used as a primary endpoint in SSc-ILD trials, further supporting the beneficial long-term effects of currently used medications. In addition, a long-term severe outcome endpoint may also support the creation of a data-driven, SSc-specific definition of ILD progression, which could then represent a solid short-term surrogate outcome and allow the identification of patients at higher risk of progression.

Risk stratification is another successful achievement in PAH, allowing the identification of patients who should then be treated more aggressively and followed up more tightly. 56 In line with lack of agreed long-term outcomes and progression definitions, preliminary data are also available for risk risk strafication of SSc-ILD. Data from a post hoc analysis of the patients with SSc-ILD receiving placebo in the SENSCIS trial identified a modest association between larger extent of fibrotic ILD at baseline and a greater decline in FVC % predicted at week 52. 57 Conversely, a post hoc analysis of the FocuSSced trial did not show the significant differences in FVC% declining in placebo group based on QILD severity, possibly related to the different outcome (decline in absolute vs % predicted FVC) and the different inclusion criteria. 58 The prognostic value of higher FVC % predicted at baseline as a factor determining a higher risk of a decline in FVC>10% predicted over the next 12 months was also confirmed in recent analysis of patients with SSc-ILD in the EUSTAR database. 19

In addition to pulmonary and other ILD features, other SSc-related extrapulmonary characteristics have shown association with ILD progression. In the same EUSTAR analysis, Hoffmann-Vold et al identified male sex, presence of reflux/dysphagia symptoms and high baseline mRSS as the strongest independent predictors of 5-year FVC decline, with significant interaction effects between time and these variables. 19 The association between oesophageal symptoms severity, even in the presence of PPI therapy, and future radiographic ILD progression was also confirmed in post analysis of SLS II study. 59 In addition to oesophageal features, early disease duration (<18 months since first non-Raynaud symptom), elevated inflammatory markers or extensive skin fibrosis (with mRSS≥18) at baseline have been also confirmed as risk factors for significant FVC decline in both the FocuSSced and the Senscis RCTs 26 60 Finally, lower SpO 2 after 6MWT and arthritis ever were identified as independent predictors of SSc-ILD progression defined as a relative decrease in FVC % ≥15%, or FVC%≥10% combined with DLCO % ≥15% at 1-year follow-up. 61

There are some limitations of this overview. First, this SLR included only articles with available full text and in English language; therefore, additional relevant studies might have been missed. Second, if an article was not identified by title or abstract as highlighting severity, progression or outcomes in SSc-ILD, it may not be detected during the screening process. Additionally, SLR was conducted in the four major electronic databases, Medline, Embase, Web of Science databases Cochrane Library, while other sources were not included.

In summary, the large heterogeneity of definitions of SSc-ILD ‘progression’, ‘severity’ and ‘outcome’ emphasise the need for further studies to develop standardised, consensus definitions, in which also patients’ perspective must be included. 62 The results of the present SLR may represent the basis for the development process to create a disease-specific model to define progression of SSc-ILD, anchored to a predetermined specific definition of severe SSc-ILD. Overall, this initiative will aim at a better understanding of the variability of the course of SSc-ILD, thus allowing an accurate stratification of patients with SSc-ILD, timely treatment initiation and development of treatments goals. 43

Acknowledgments

on behalf of the SILPRO project investigators.

Twitter: @cosimobruni

Contributors: Criterion 1: (a) substantial contributions to study conception and design: CB, OD. (b) Substantial contributions to acquisition of data: LP, FB, CC, EF, SP, ST, PB, CC, RDL, AE, JL, CB. (c) Substantial contributions to analysis and interpretation of data: all authors. Criterion 2: drafting the article or revising it critically for important intellectual content: all authors. Criterion 3: final approval of the version of the article to be published: all authors. Guarantor: CB.

Funding: The study was supported by the 2021 Betty Z Benedict research grant by the Scleroderma Clinical Trial Consortium (SCTC) and the Scleroderma Research Foundation (SRF).

Competing interests: Liubov Petelytska Grant/research support from: received research grant from Swiss National Research Foundation/Scholars at risk. Francesco Bonomi, Carlo Cannistrà, Elisa Fiorentini, Silvia Peretti, Sara Torracchi, Pamela Bernardini, Carmela Coccia, Riccardo De Luca, Alessio Economou, Juela Levani: None declared. Marco Matucci-Cerinic: Speakers bureau: Actelion, Janssen, Inventiva, Bayer, Biogen, Boehringer, CSL Behring, Corbus, Galapagos, Mitsubishi, Samsung, Regeneron, Acceleron, MSD, Chemomab, Lilly, Pfizer, Roche., Consultant of: Actelion, Janssen, Inventiva, Bayer, Biogen, Boehringer, CSL Behring, Corbus, Galapagos, Mitsubishi, Samsung, Regeneron, Acceleron, MSD, Chemomab, Lilly, Pfizer, Roche. Distler O: Consultancy relationship with and/or has received research funding from and/or has served as a speaker for the following companies in the area of potential treatments for systemic sclerosis and its complications in the last three calendar years: 4P-Pharma, Abbvie, Acceleron, Alcimed, Altavant, Amgen, AnaMar, Arxx, AstraZeneca, Blade, Bayer, Boehringer Ingelheim, Corbus, CSL Behring, Galderma, Galapagos, Glenmark, Gossamer, Horizon, Janssen, Kymera, Lupin, Medscape, Merck, Miltenyi Biotec, Mitsubishi Tanabe, Novartis, Prometheus, Redxpharma, Roivant and Topadur. Patent issued “mir-29 for the treatment of systemic sclerosis” (US8247389, EP2331143). Co-founder of CITUS AG. Editorial Board member for Annals of the Rheumatic Diseases, RMD Open. Cosimo Bruni Speakers bureau: Eli- Lilly, Consultant of: Boehringer Ingelheim, Grant/research support from: Gruppo Italiano Lotta alla Sclerodermia (GILS), European Scleroderma Trials and Research Group (EUSTAR), Foundation for research in Rheumatology (FOREUM), Scleroderma Clinical Trials Consortium (SCTC), Scleroderma Research Foundation (SRF). Educational grants from AbbVie and Wellcome Trust. Congress Support from: Boehringer Ingelheim.

Provenance and peer review: Not commissioned; externally peer reviewed.

Supplemental material: This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

Data availability statement

Ethics statements, patient consent for publication.

Not applicable.

Ethics approval