Between-group psychotherapy outcome research and basic science

In this paper, a view of the nature, purpose, and methods of experimentally controlled between-group therapy outcome research is presented. It is argued that the greatest progress in the development of increasingly useful interventions based on between-group therapy designs will come from (a) viewing such controlled therapy outcome research as basic science in which knowledge is acquired through experimental designs constructed to yield specific cause-and-effect conclusions and (b) combining this form of research with the clinical and nonclinical types more commonly called 'basic research'.