On this page
- Systematic reviews, a more specific guide for conducting systematic reviews from a health sciences perspective.
- Academic writing: what is a literature review, a guide that addresses the writing and composition aspect of a literature review
- Media literature reviews: how to conduct a literature review using news sources
- Literature reviews in the applied sciences
- Start your research here, literature review searching, mainly of interest to newer researchers
For more assistance, please contact the Liaison Librarian in your subject area.
What is a literature review?
Most generally, a literature review is a search within a defined range of information source types, such as, for instance, journals and books, to discover what has been already written about a specific subject or topic. A literature review is a key component of almost all research papers. However, the term is often applied loosely to describe a wide range of methodological approaches. A literature review in a first or second year course may involve browsing the library databases to get a sense of the research landscape in your topic and including 3-4 journal articles in your paper. At the other end of the continuum, the review may involve completing a comprehensive search, complete with documented search strategies and a listing of article inclusion and exclusion criteria. In the most rigorous format - a Systematic Review - a team of researchers may compile and review over 100,000 journal articles in a project spanning one to two years! These are out of scope for most graduate students, but it is important to be aware of the range of types of reviews possible.
One of the first steps in conducting a lit review is thus to clarify what kind of review you are doing, and its associated expectations.
Factors determining review approach are varied, including departmental/discipline conventions, granting agency stipulations, evolving standards for evidence-based research (and the corollary need for documented, replicable search strategies), and available time and resources.
The standards are also continually evolving in light of changing technology and evidence-based research about literature review methodology effectiveness. The availability of new tools such as large-scale library search engines and sophisticated citation management software continues to influence the research process.
Some specific types of lit reviews types include systematic reviews, scoping reviews, realist reviews, narrative reviews, mapping reviews, and qualitative systematic reviews, just to name a few. The protocols and distinctions for review types are particularly delineated in health research fields, but we are seeing conventions quickly establishing themselves in other academic fields.
Literature review type definitions
The below definitions are quoted from the very helpful book, Booth, A., Papaioannou, D., & Sutton, A. (2012). Systematic approaches to a successful literature review. London: SAGE Publications Ltd.
For more definitions, try:
- Grant, M.J. & Booth, A. (2009). A typology of reviews: an analysis of the 14 review types and associated methodologies. Health Information & Libraries Journal, 26(2), 91-108. doi: 10.1111/j.1471-1842.2009.00848.x
- Sage Research Methods Online. A database devoted to research methodology. Includes handbooks, encyclopedia entries, and a research concepts map.
- Individual books found under these subject headings:
Note: There is unfortunately no subject heading specifically for "literature reviews" which brings together all related material.
Mapping Review: "A rapid search of the literature aiming to give a broad overview of the characteristics of a topic area. Mapping of existing research, identification of gaps, and a summary assessment of the quantity and quality of the available evidence helps to decide future areas for research or for systematic reviews." (Booth, Papaioannou & Sutton, 2012, p. 264)
Mixed Method Review: "A literature review that seeks to bring together data from quantitative and qualitative studies integrating them in a way that facilitates subsequent analysis" (Booth et al., p. 265).
Meta-analysis: "The process of combining statistically quantitative studies that have measured the same effect using similar methods and a common outcome measure" (Booth et al., p. 264).
Narrative Review: "A term used to describe a conventional overview of the literature, particularly when contrasted with a systematic review" (Booth et al., p. 265).
Note: this term is often used pejoratively, describing a review that is inadvertently guided by a confirmation bias.
Qualitative Evidence Synthesis: "An umbrella term increasingly used to describe a group of review types that attempt to synthesize and analyze findings from primary qualitative research studies" (Booth et al., p. 267).
Rapid Review: "Assessment of what is already known about a policy or practice issue, by using systematic review methods to search and critically appraise existing research" (Grant & Booth, 2009, p.96).
Note: Rapid reviews are often done when there are insufficient time and/or resources to conduct a systematic review. As stated by Butler et. al, "They aim to be rigorous and explicit in method and thus systematic but make concessions to the breadth or depth of the process by limiting particular aspects of the systematic review process" (as cited in Grant & Booth, 2009, p. 100).
Scoping Review: "A type of review that has as its primary objective the identification of the size and quality of research in a topic area in order to inform subsequent review" (Booth et al., p. 269).
Systematic Review: "A review of a clearly formulated question that uses systematic and explicit methods to identify, select and critically appraise relevant research and to collect and analyse data from the studies that are included in the review" (Booth et al., p. 271).
Note: a systematic review (SR) is the most extensive and well-documented type of lit review, as well as potentially the most time-consuming. The idea with SRs is that the search process becomes a replicable scientific study in itself. This level of review will possibly not be necessary (or desirable) for your research project.
Literature review protocols and guidelines
Many lit review types are based on organization-driven specific protocols for conducting the reviews. These protocols provide specific frameworks, checklists, and other guidance to the generic literature review sub-types. Here are a few popular examples:
Cochrane Review - known as the "gold standard" of systematic reviews, designed by the Cochrane Collaboration. Primarily used in health research literature reviews.
- Cochrane Handbook for Systematic Reviews of Interventions. "The official document that describes in detail the process of preparing and maintaining Cochrane systematic reviews".
Campbell Review - the sister organization of the Cochrane Institute which focuses on systematic reviews in the social sciences.
- So you want to write a Campbell Systematic review?
- Campbell Information Retrieval Guide. The details of effective information searching
Rapid Reviews have become increasingly common due to their flexibility, as well as the lack of time and resources available to do a comprehensive systematic review. McMaster University's National Collaborating Centre for Methods and Tools (NCCMT) has created a Rapid Review Guidebook, which "details each step in the rapid review process, with notes on how to tailor the process given resource limitations."
There is no strict protocol for a scoping review (unlike Campbell and Cochrane reviews). The following are some recommended guidelines for scoping reviews:
- Joann Briggs' Reviewers' Manual for Scoping Reviews
- HL Wiki's Scoping Reviews
- Current best practices for the conduct of scoping reviews, from the EQUATOR Network
In addition to protocols which provide holistic guidance for conducting specific kinds of reviews, there are also a vast number of frameworks, checklists, and other tools available to help focus your review and ensure comprehensiveness. Some provide broader-level guidance; others are targeted to specific parts of your reviews such as data extraction or reporting out results.
- PICO or PICOC A framework for posing a researchable question (population, intervention, comparisons, outcomes, context/environment)
- PRISMA Minimum items to report upon in a systematic review
- SALSA framework: frames the literature review into four parts: search (S), appraisal(AL), synthesis(S), analysis(A)
- STARLITE Minimum requirements for reporting out on literature reviews.
- Critical Appraisal Skills Program (CASP) Checklists Includes a checklist for evaluating Systematic Reviews.
These are just a sampling of specific guides generated from the ever-growing literature review industry.
To Google Scholar, or not to Google Scholar
Much of the online discussion about the use of Google Scholar in literature reviews seems to focus more on values and ideals, rather than a technical assessment of the search engine's role. Here are some things to keep in mind.
- It's good practice to use both Google Scholar and subject-specific databases (example: PsycINFO) for conducting a lit review of any type. For most graduate-level literature reviews, it is usually recommended to use both.
- You should search Google Scholar through the library's website when off-campus. This way you can avoid being prompted for payment to access articles that the SFU Library already subscribes to.
- Search tips for Google and Google Scholar
- Allows you to cast a wide net in your search.
- The most popular articles are revealed
- A high volume of articles are retrieved
- Google's algorithm helps compensate for poorly designed searches
- Full-text indexing of articles is now being done in Google Scholar
- A search feature allow you to search within articles citing your key article
- Excellent for known-item searching or locating a quote/citation
- Helpful when searching for very unique terminology (e.g., places and people)
- Times cited tool can help identify relevant articles
- Extensive searching of non-article, but academic, information items: universities' institutional repositories, US case law, grey literature, academic websites, etc.
- The database is not mapped to a specific discipline
- Much less search sophistication and manipulation supported
- Psuedo-Boolean operators
- Missing deep data (e.g., statistics)
- Mysterious algorithms and unknown source coverage at odds with the systematic and transparent requirement of a literature review.
- Searches are optimized (for example, by your location), thwarting the replicability criteria of most literature review types
- Low level of subject and author collocation - that is, bringing together all works by one author or one sub-topic
- Challenging to run searches that involve common words. A search for "art AND time", for example, might bring up results on the art of time management when you are looking for the representation of time in art. In contrast, searching by topic is readily facilitated by use of subject headings in discipline-specific databases. Google Scholar has no subject headings.
- New articles might not be pushed up if the popularity of an article is prioritized
- Indexes articles from predatory publishers, which may be hard to identify if working outside of your field
Unlike Google Scholar, subject specific databases such as PsycINFO, Medline, or Criminal Justice Abstracts are mapped to a disciplinary perspective. Article citations contain high-quality and detailed metadata. Metadata can be used to build specific searches and apply search limits relevant to your subject area. These databases also often offer access to specialized material in your area such as grey literature, psychological tests, statistics, books and dissertations.
For most graduate-level literature reviews, it is usually recommended to use both. Build careful searches in the subject/academic databases, and check Google Scholar as well.
Subject headings vs. Keywords
For most graduate-level lit reviews, you will want to make use of the subject headings (aka descriptors) found in the various databases.
Subject headings are words or phrases assigned to articles, books, and other info items that describe the subject of their content. They are designed to succinctly capture a document's concepts, allowing the researcher to retrieve all articles/info items about that concept using one term. By identifying the subject headings associated with your research areas, and subsequently searching the database for other articles and materials assigned with that same subject heading, you are taking a significant measure to ensure the comprehensiveness of your literature review.
About subject headings:
- They are applied systematically: articles and books will usually have about 3-8 subject headings assigned to their bibliographic record.
- The subject headings come from a finite pool of terms - one that is updated frequently.
- They are often organized in a hierarchical taxonomy, with subject headings belonging to broader headings, and/or having narrower headings beneath them. Sometimes there are related terms (lateral) as well.
- They provide a standardized way to describe a concept. For instance, a subject heading of "physician" may be used to capture many of the natural language words that describe a physician such as doctor, family doctor, GP, and MD.
One way to identify subject headings (SHs) of interest to you is to start with a keyword search in a database, and see which SHs are associated with the articles of interest.
A. In the below example, we start with a keyword search for "type a" personality in PsycINFO. A more contemporary term to describe this phenomena is then found in the subject heading field:
B. Another way to identify subject headings related to your topic is to go directly to a database's thesaurus or index. For example, if we are researching depression, the PsycINFO entry for major depression suggests some narrower terms we could focus our search by.
For more in-depth help with using subject headings in a literature review, please contact the Liaison Librarian in your subject area.
Keeping track of your research
Project management software
- NVivo is a robust software package that helps with management and analysis of qualitative information.The Library's Research Commons offers extensive support for NVivo.
- Research Support Software offered by the Research Commons
Citation management software
Citation management software such as Mendeley or Zotero is essential for completing a substantial lit review. Citation software is a centralized, online location for managing your sources. Specifically, it allows you to:
- Access and manage your sources online, all in one place
- Import references from library databases and websites
- Automatically generate bibliographies and in-text citations within Microsoft Word
- Share your collection of sources with others, and work collaboratively with references
- De-duplicate your search results
- Annotate your citations. Some software allows you to mark up PDFs.
- Note trends in your research such as which journals or authors you cite from the most.
Did you know that many databases allow you to save your search strategies? The advantages of saving and tracking your search strategies online in a literature review include:
- Developing your search strategy in a methodological manner, section by section. For instance, you can run searches for all synonyms and subjects headings associated with one concept, then combine them with different concepts in various combinations.
- Re-running your well-executed search in the future
- Creating search alerts based on a well-designed search, allowing you to stay notified of new research in your area
- Tracking and remember all of the searches you have done. Avoid inadvertently re-doing your searches by being well-documented and systematic as you go along - it's worth the extra effort!
Databases housed on the EBSCO plaform (examples: Business Source Complete, PsycINFO, Medline, Academic Search Premier) allow you to create an free account where you might save your searches: