Theory and Practice of Meta-Analysis

ABSTRACT

Decisions about the utility of an intervention or the validity of a hypothesis should not be based on results of a single study, because different studies provide different results. Hence, a data synthesizing mechanism is required. Meta-analysis is the statistical procedure for combining data from multiple studies. When the treatment effect is consistent across different studies, metaanalysis can identify the common effect. When the treatment effect varies in studies, meta-analysis may identify reasons for variations. Meta-analysis is a powerful tool, though awareness of its limitations and possible errors for correct application are essential.