Abstract
This article examines the usefulness of meta‐analysis, and articulates many of the criticisms that have been made of its workings. An attempt is made to outline the precautions that have to be taken before a scientifically useful and meaningful meta‐analysis can be carried out. The problems encountered include heterogeneity of samples, conditions, interventions and end‐points; narrow focus; curvilinearity of regression; lack of independence of determinants; synergistic interactions; contradictory experimental results. It is suggested that best‐evidence synthesis, or theorydirected analysis, might be a safer option.

This publication has 24 references indexed in Scilit: