Meta-analysis refers to methodologies that are used to integrate related empirical research to arrive at conclusions not possible by reviewing individual studies, or to improve generalizations of individual studies. It is distinguished from the traditional narrative review in that statistical methodologies are applied to derive more objective conclusions than those that typify narrative reviews. Meta-analysis has been slow to appear in the literature of clinical medicine, however, particularly when viewed in the context of the exponential expansion of literature and the availability of computer technology to facilitate its conduct.