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Levy Library Research Synthesis and Systematic Review Services: Literature Reviews

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What Is a Literature Review?

Pile of differently colored books

A literature review conveys all relevant information on a given topic. It can use a wide variety of materials, such as journal articles, books, and guidelines. Literature reviews can be standalone or part of a larger work, such as serving as an introduction to an empirical paper.



Literature reviews are useful for:

  • Providing an overview of main theories and hypotheses, appropriate methods and methodologies, and key findings
  • Helping readers discover the key authors/researchers on a topic
  • Identifying knowledge gaps

Limitations of literature reviews include the possibility of introducing bias and issues related to reproducibility. 


  1. Grant MJ, Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies. Health information & libraries journal. 2009 Jun;26(2):91-108.

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Systematic Reviews vs. Literature Reviews

It is important to understand the difference between systematic reviews (with or without meta-analysis) and literature reviews.

Systematic reviews seek to answer a specific and clearly formulated question by using rigorous, explicit protocols to identify, select and appraise relevant research studies; and to collect and analyze data from the selected studies. To minimize bias, systematic reviews include or exclude evidence on the basis of explicit quality criteria. They may incorporate meta-analysis.

Literature reviews, often just called Reviews, articles may be evidence-based, but they are not evidence. Rather than answering a specific clinical question, they provide an overview of the research landscape on a given topic. They usually lack systematic search protocols or explicit criteria for selecting and appraising evidence. 

Systematic Reviews
Literature Reviews
Investigate a clearly defined, often very specific topic or question. (e.g. To assess the efficacy and safety of ustekinumab in patients with moderate to severe plaque psoriasis.) Typically provides a broadstrokes view of research in given area. (e.g. New treatment options for psoriasis.)
Literature is gathered using explicit search protocols. Extensive searching may be conducted, but an explicit, systematic literature search protocol not typically used.
Studies selected for the review using a protocol that specifies inclusion, exclusion criteria. Studies used to support the reviewers' recommendations are not selected according to a set of predetermined inclusion/exclusion criteria.
A critical appraisal process takes place, examining the quality of each study and determining the validity of its results.  Studies may be graded according to an established set of criteria. May or may not use a level of evidence rating system to "grade" the quality and strength of individual studies.
Data from primary study may be synthesized in a meta-analysis. Literature reviews typically do no included a quantitative aspect.
When evidence is lacking, the authors usually recommend further research. When evidence is lacking, the authors make recommendations based on their opinions and experience. They made grade the strength of the recommendations depending on the strength of the underlying evidence used to arrive at the recommendation.