THE USE OF METAANALYSIS IN PSYCHOTHERAPY OUTCOME RESEARCH

This paper examines the logical foundations of research integration. The qualitative review is found wanting. Meta-analytic procedures which emphasize effect size and decrease the overemphasis on single studies, are proposed as more appropriate alternatives. The now classic analyses by Glass and colleagues represent the introduction of meta-analysis to the field of psychotherapy evaluation. A critical evaluation of these studies exemplify fundamental issues within meta-analytic methodology. Alternative approaches to meta-analysis are presented within the context of the methodological issues which actualized their developments. Accumulating research is likely to be more complete, more explicit and quantitative with the use of meta-analysis. Recent developments give considerate promise for gaining information about causal moderators and causal efficacious treatment components.