ABSTRACT
Meta-analysis, the science of combining quantitative estimates from a number of different studies, was named such by Glass in 1976 (1). In the twenty years since its inception, an array of different methods, often of increasing sophistication, have been developed for the pooling of estimates from primary studies. While a brief overview of the most common methods is given below, the reader who is unfamiliar with any of the methodology is strongly advised to seek other sources (such as Refs 2 and 3) for clarification.
