“A review of the literature consists of reading, analyzing, and writing a synthesis of scholarly materials about a specific topic. When the review is of scientific literature, the focus is on the hypotheses, the scientific methods, the strengths and weaknesses of the study, the results, and the authors’ interpretations and conclusions. A review of the scientific literature is fundamental to understanding the accumulated knowledge about the topic being reviewed" (Gerard, 2017).
When you're writing a literature review, you won't just summarize all of the articles that you've found on your topic. Instead, you'll synthesize the evidence. This means that you'll look at the state of the evidence as a whole, telling your reader what it means when you put it all together. Rather than reviewing your sources one at a time, you'll organize your lit review by concept, chronology, methodology, etc. -- whatever makes the most sense for your topic.
This video from the North Carolina State Libraries offers a thorough 10-minute introduction to literature reviews. It's a great resource if you still aren't sure how to approach your lit review.
Garrard, J. (2017). Health sciences literature review made easy: The matrix method. Burlington, MA: Jones and Bartlett Learning.
Libncsu [Username]. (July 30, 2009). Literature reviews: An overview for graduate students [Video]. Youtube. Retrieved April 29, 2020 from https://www.youtube.com/watch?v=t2d7y_r65HU&feature=youtu.be
University of North Carolina Writing Center. (n.d.). Literature reviews. Retrieved April 29, 2020 from https://writingcenter.unc.edu/tips-and-tools/literature-reviews
Here you will find descriptions of narrative, integrative, and systematic reviews. You will also find additional information about finding and understanding systematic reviews. Once you understand what a systematic review is and where to search for them, see the Search Tips page in this guide for help with finding the articles you need.
| Narrative Review | Integrative Review | Systematic Review |
|---|---|---|
| Purpose: address a specific question with a summary of previous findings and an implicit conclusion | Purpose: wide range of purposes - define concepts, review theories, review evidence, analyze methodological issue of a topic | Purpose: in response to an answerable, clinical question |
| Literature includes: there is not necessarily an orderly process, so a broad overview of the topic is often presented through primary and secondary sources | Literature includes: diverse methodologies - experimental and non-experimental; theoretical and empirical literature. Explicit strategies and inclusion/exclusion criteria recommended | Literature includes: primary studies based on explicit search strategies and inclusion/exclusion criteria |
| Evidence Level: not included in the levels of evidence | Evidence Level: informally considered to be mid-level in the evidence hierarchies | Evidence Level: universally considered to be at the highest level in the evidence hierarchies |
| Biases: this type of review relies on the author's expert opinion, and often only articles that support that opinion are included | Biases: it's possible for authors to choose studies arbitrarily considered to most relevant for supporting their own opinions or research hypotheses | Biases: the explicit structures and strategies reduce the potential for author bias that exists in narrative and integrative reviews |
From the Oak Ridge Institute for Science and Education
"Literature reviews in the introduction to a report provide readers with an overview of existing evidence, and contribute to the argument for the new study. These reviews are usually only 2 to 4 double spaced pages, and so, only key studies can be cited. The emphasis is on summarizing and evaluating an overall body of evidence" (Polit & Beck, 2012).
"An integrative review is a specific review method that summarizes past empirical or theoretical literature to provide a more comprehensive understanding of a particular phenomenon or healthcare problem...Well-done integrative reviews present the state of the science, contribute to theory development, and have direct applicability to practice and policy" (Whittemore & Knafl, 2005).
If you're conducing an integrative review, read Whittemore and Knafl because they clearly explain what an integrative review is and how to design and implement one.
A systematic review attempts to identify, appraise and synthesize all the empirical evidence that meets pre-specified eligibility criteria to answer a specific research question. Researchers conducting systematic reviews use explicit, systematic methods that are selected with a view aimed at minimizing bias, to produce more reliable findings to inform decision making. See the Cochrane Library
"A systematic review involves the identification, selection, appraisal, and synthesis of the best available evidence for clinical decision making. A properly conducted systematic review uses reproducible, preplanned strategies to reduce bias and instill rigor and pools information from both published and unpublished sources... Systematic reviews are conducted to answer specific, often narrow, clinical questions. These questions are formulated according to the mnemonic PICO addressing: a specific population (P) (such as people traveling long distance), the intervention of interest (I) (e.g., preventive measures for deep vein thrombosis), an optional comparison (C) (such as the standard of care, which may be no intervention), and one or more specific outcomes (such as prevention of deep vein thrombosis)" (Kazer & Fitzpatrick, 2012).
Meta-analysis is a quantitative approach that permits the synthesis and integration of results from multiple individual studies focused on a specific research question. A meta-analysis is a rigorous alternative to the traditional narrative review of the literature. It involves the application of the research process to a collection of studies in a specific area. The individual studies are considered the sample.
A systematic review may include meta-analysis if it is able to combine the results of comparable randomized controlled trials. See Systematic Review in the Encyclopedia of Nursing Research.
Kazer, M. W., & Fitzpatrick, J. J. (2012). Systematic Reviews. In The Encyclopedia of Nursing Research, Third Edition. New York, NY: Springer Publishing Company. https://ezproxy.simmons.edu/login?url=https://search.ebscohost.com/login.aspx?direct=true&db=nlebk&AN=387241&site=ehost-live&scope=site&ebv=EB&ppid=pp_500
Polit, D. F., & Beck, C. T. (2012). Nursing research: Generating and assessing evidence for nursing practice. Lippincott Williams & Williams.
Whittemore R, & Knafl K. (2005). The integrative review: Updated methodology. Journal of Advanced Nursing. 52(5), 546–553. https://doi-org.ezproxy.simmons.edu/10.1111/j.1365-2648.2005.03621.x
For a narrative review as part of a research report, you want to conduct a comprehensive search to identify as many sources as possible on your topic. You'll then choose the key studies to include in your report.
Search health sciences databases (i.e. Cinahl, Medline) for keywords related to your topic. (See the Search Basics page of this guide for tips and resources). Having trouble? Meet with a librarian with a librarian to discuss databases, keywords, and search strategies.
When you find a relevant article, use it to identify other potentially relevant articles: Look at its references to identify other relevant articles that you haven't found. Use Google Scholar or Scopus to identify more recent articles that have cited that one. Reviews that are part of a research report don't usually share their search strategy, but it's still a good idea to take notes to make the process as organized and efficient as possible.
It is important to clearly document search strategies in the methods sections. This lets your readers know exactly how you identified the studies in your review and makes your search replicable. For example:
Not every article that comes up in your search will be appropriate for your review. As you examine your search results, come up with specific criteria that makes an article not suitable to be included. Some examples include:
A synthesis matrix helps you compare research articles side-by-side so you can identify common themes and visualize the bigger picture.
Clark, K. R., & Buckley, M. B. (2017). Using a synthesis matrix to plan a literature review. Radiologic Technology, 88(3), 354–357. https://ezproxy.simmons.edu/login?url=https://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=120516438&site=ehost-live&scope=site
Garrard, J. (2017). Health sciences literature review made easy: The matrix method. Fifth edition. Jones & Bartlett Learning. https://ezproxy.simmons.edu/login?url=https://search.ebscohost.com/login.aspx?direct=true&db=nlebk&AN=1229455&site=ehost-live&scope=site
