Meta-analysis: Heterogeneity can be a good thing

Meta-analysis is widely used to address important and dispirit problems in public health and medicine. Meta-analysis seeks to summarize the results of a number of different studies on a common topic. Heterogeneity in the results is common. Sometimes, perceived heterogeneity is a motivation for the use of meta-analysis in order to understand and reconcile differences. In other cases the presence of heterogeneity is regarded as a reason not to summarize results. An important role for meta-analysis is the determination of design and analysis factors that influence the outcome of studies. In this talk, I will review some of the contributions and controversies of meta-analysis in public health and discuss the examination and resolution of heterogeneity.