School of Medicine

The Pulse

Is Your Review Really a Systematic Review? (Part 1)

Julie H. Schiavo, MLIS, AHIP
Assistant Director, Dental Services
School of Dentistry Liaison

Systematic reviews are considered the highest form of evidence used when practicing evidence-based medicine and the publication of systematic reviews has risen dramatically in the past 20 years. In fact, a PubMed search for the words “systematic review” in an article title yields nearly 170,000 citations. Of those citations, 526 of those were published in 2002 and 36,791 were published in 2021. However, sometimes the concept of a systematic review is lost within this significantly large number published. There are many types of review articles with different methodological rigor, accountability, and usefulness. How can you tell the difference between a true systematic review and other types of review articles?

A systematic review is defined as a “a review of existing research using explicit, accountable rigorous research methods”1.  It is considered a high-level synthesis of available evidence done to answer a specific question by following a detailed method to retrieve and appraise studies, and adhering to uniform guidelines on the conduct of the review. The goal is to gather what is known, discover what is still unknown, reveal the uncertainty surrounding the evidence, and make practice recommendations. Systematic reviews begin with an explicit and answerable research question. Studies are gathered in exhaustive searches of several databases to discover as much evidence as possible. (Contact the library for assistance with the literature search. We are trained to do this!) Each study is assessed for inclusion or exclusion, then assessed for quality and bias. The included studies are synthesized in a narrative and a synthesis table included in the final review.2 

One of the most important element of a systematic review is that it is reproducible. There must be enough detail in the finished article for someone else to replicate your review. There are many guidelines for conducting a systematic review available for researchers. These guidelines vary by discipline, geographic location, and sponsoring organization. The most popular is, arguably, the Preferred Reporting Items for Systematic Reviews and Meta Analysis or PRISMA (http://www.prisma-statement.org/). The PRISMA Statement can guide you through the process of creating a systematic review and lists all the elements that must be included in the final review.3

Systematic reviews require quite a bit of time and effort to complete. It is usually recommended that you have a team of at least three reviewers and a librarian working on your review. Also, plan on it taking at least nine months to complete. If you are interested in conducting a systematic review, contact the library early in the process. We can help guide you through the planning process, conduct your literature searches, and write the methodology section of the completed review.

If your project does not meet the requirements of a true systematic review, don't give up on it! Next time, we will cover the various types of review articles and what sets them apart from the systematic review.

References

  1. Gough D, Thomas J. In: Introduction to Systematic Reviews. Gough D, Oliver S, Thomas J, editor. Sage, London; 2012.
  2. Gough D, Thomas J, Oliver S. Clarifying differences between review designs and methods. Syst Rev. 2012 Jun 9;1:28. doi: 10.1186/2046-4053-1-28. 
  3. Moher D, Liberati A, Tetzlaff J, Altman DG. The PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA Statement. PLoS Med. 2009;6:6. doi: 10.1371/journal.pmed.1000006.