How to Guides: Systematic Reviews

A systematic review is a protocol-driven, comprehensive literature review, designed to answer a well defined question. It involves using a specific research methodology with internationally accepted characteristics.

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.

Systematic reviews may also contain meta-analyses. Meta-analysis is the use of statistical methods to summarize the results of independent studies. By combining information from all relevant studies, meta-analyses can provide more precise estimates of the effects of health care than those derived from the individual studies included within a review (see The Cochrane Handbook Chapter 10). They also facilitate investigations of the consistency of evidence across studies, and the exploration of differences across studies.

Citation: Cochrane Handbook for Systematic Reviews of Interventions version 6.0

Acknowledgement - much of the content in this guide has been adapted / copied from the Yale University's Harvey Cushing / John Hay Whitney Medical Library's guide on systematic reviews and other comprehensive searching guide.

Ensuring the rigor in systematic reviews: Part 1, the overview - Heart & Lung - Sep-Oct 2020

Ensuring the rigor in systematic reviews: Part 2, preparation is key: The question and the protocol - Heart & Lung - 26 Aug 2020

Grey literature is “information produced by all levels of government, academics, business and industry in electronic and print formats not controlled by commercial publishing”, (GreyNet) and includes materials such as theses and dissertations, working papers, policy statements, technical reports and government documents.

Why include grey literature in your review?

For completeness. Whilst it is rarely peer-reviewed, grey literature is often a good source of the most up-to-date information on a topic. Including it reduces publication bias and it may be the only source of some data.

The AACODS checklist is a useful method to quickly evaluate grey literature. Authority  Accuracy  Coverage  Objectivity Date  Significance   Tyndall, J. AACODS Checklist. Flinders University, 2010.