A practical guide to understanding systematic reviews and meta-analyses.

A systematic review is a transparent and unbiased review of available information. The published systematic review must report the details of the conduct of the review as one might report the details of a primary research project. A meta-analysis is a powerful and rigorous statistical approach to synthesize data from multiple studies, preferably obtained from a systematic review, in order to enlarge the sample size from smaller studies to test the original hypothesis and/or to generate new ones. The objective of this article is to serve as an easy to read practical guide to understand systematic reviews and meta-analyses for those reading them and for those who might plan to prepare them.