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Systematic Reviews

This guide explains the principles of systematic reviews and offers advice on getting started with your systematic literature search.

Systematic Reviews and the UCLA Library

Working on a systematic review? Librarians at the UCLA Biomedical Library can help you! The UCLA Biomedical Library offers a systematic review service to research staff, graduate students and faculty in all departments. To initiate a consultation about your systematic review click through to our Biomedical Library Expert Search Services (BLESS) portal.

Our service offers guidance and collaboration in the following areas:

  • Choosing the best review methodology to fit your timeline, question, and discipline
  • Selecting search terms, databases, and expert search strategies
  • Developing and delivering finalized search strategies
  • Organizing search results using citation management (EndNote)
  • Writing the methodology section

Due to staffing levels, we are only able to work on a few systematic reviews simultaneously.

What Is a Systematic Review?

A systematic review is fundamentally different from a traditional narrative review. For more information, see Types of Literature Reviews.

A systematic review is defined as: "A scientific investigation that focuses on a specific question and that uses explicit, planned scientific methods to identify, select, assess, and summarize the findings of similar but separate studies. It may or may not include a quantitative synthesis of the results from separate studies (meta-analysis) depending on the available data." IOM p 1.

According to the Cochrane Handbook, section 1.2.2, "the key characteristics of a systematic review are:

  • a clearly stated set of objectives with pre-defined eligibility criteria for studies;
  • an explicit, reproducible methodology;
  • a systematic search that attempts to identify all studies that would meet the eligibility criteria;
  • an assessment of the validity of the findings of the included studies, for example through the assessment of risk of bias; and
  • a systematic presentation, and synthesis, of the characteristics and findings of the included studies."

Green S, Higgins JPT, Alderson P, Clarke M, Mulrow CD, Oxman AD. Chapter 1: Introduction. In: Higgins JPT, Green S (editors), Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (updated March 2011). The Cochrane Collaboration, 2011. Available from www.cochrane-handbook.org.

Is Your Review Systematic?

Are you sure your review is systematic? A systematic review requires…

You can also use this primer geared towards beginners for a better understanding of the differences between types of reviews and the overall steps of a systematic review:

  • Craig A. Umscheid; A Primer on Performing Systematic Reviews and Meta-analyses, Clinical Infectious Diseases, Volume 57, Issue 5, 1 September 2013, Pages 725–734, https://doi.org/10.1093/cid/cit333

Why Do a Systematic Review?

The goal of a systematic review is to reduce bias and produce high quality evidence.

Rigorous systematic reviews are at the top of representations of research evidence (see below). The synthesis of multiple high-quality studies creates a single product out of all the best known evidence.