How to Review a Meta-analysis

Abstract

Meta-analysis is a systematic review of a focused topic in the literature that provides a quantitative estimate for the effect of a treatment intervention or exposure. The key to designing a high quality meta-analysis is to identify an area where the effect of the treatment or exposure is uncertain and where a relatively homogenous body of literature exists. The techniques used in meta-analysis provide a structured and standardized approach for analyzing prior findings in a specific topic in the literature. Meta-analysis findings may not only be quantitative but also may be qualitative and reveal the biases, strengths, and weaknesses of existing studies. The results of a meta-analysis can be used to form treatment recommendations or to provide guidance in the design of future clinical trials.

Keywords: Meta-analysis; bias; statistic.

Figure 1

Example of funnel plot demonstrating no publication bias where the estimated true risk is 4. Risk estimates are evenly distributed around true risk (A). Example of funnel plot demonstrating publication bias where the estimated true risk is 4. Risk estimates cluster in lower right-hand corner, indicating that small studies with positive results are more likely to be published (B).