An Introduction to Meta-Analysis

Abstract

Health information has grown exponentially in recent years, and evidence-based practice has become the new paradigm of healthcare. In the absence of robust information synthesis, traditional nonsystematic or narrative reviews that are based on the reviewers’ prior experience or expert opinions cannot be reproduced. With the rapid pace of innovation and new studies that supersede old information, such reviews are at risk of becoming outdated. Consequently, carefully conducted and reproducible reviews that employ framing of relevant research questions, well-specified algorithms to search literature databases and research databases of primary studies, and synthesis of information are very important to obtain reproducible reviews necessary for developing practice guidelines. Such explicit reviews of the literature are known as systematic reviews. In meta-analysis, findings from similar but unique studies are statistically synthesized. In this chapter, the principles and practice of meta-analysis are presented.