Establishing Causal Connections: Meta‐Analysis and Psychotherapy

Meta‐analysis is a new quantitative technique for integrating diverse empirical data. It has been used most notably to establish causal connections between psychotherapy and beneficial therapeutic outcomes (Smith, Glass, and Miller 1980), but it has also been applied to a variety of other causal problems, including the effects of drug therapies on psychological disorders; the effects of school class size on attainment; sex differences in conformity; experimenter effects; the effects of self‐serving bias; and the relationship between social class and achievement. The technique is also likely to be widely used in the future in a variety of areas of the social sciences; one commentator has already referred to the “.meta‐analytic revolution”. in outcome research (Fiske 1983).