ABSTRACT
This chapter reviews research on the effectiveness of group work with children, adolescents, and adults across a variety of settings. Meta-analysis is a specific quantitative technique that aggregates the results of numerous clinical trials using a meaningful quantitative index, commonly known as an effect size (ES). Thus, an ES is an index score reported in standard deviation units. The process variables in group work can be complex and difficult to isolate and analyze because of the holistic nature of human interaction. Ordinarily, group process variables include facets such as group planning characteristics, group structure, pre-group training, and therapeutic factors. Therapeutic factors appear to affect different populations and member disorders differently and even at different stages of group development. Group treatment of depression and bipolar disorder in adults is quite effective. Group interventions for members with these mood disorders appear helpful in providing interpersonal support, effective coping skills, and understanding of the nature and course of the conditions.
