Psychotherapy outcome studies do not accurately represent current models of psychotherapy. A proposed remedy.

It is argued that the design of contemporary psychotherapy outcome studies is conceptually incompatible with the models of psychotherapy evaluated in those studies. Contemporary outcome studies are incompatible with psychotherapy models because the outcome studies treat patients with standardized treatments that are assigned on the basis of psychiatric diagnosis rather than with individualized treatments based on a theory-driven psychological assessment of the individual's difficulties. One possible remedy, idiographic outcome studies using a case formulation model of assessment and treatment, is proposed here. It is suggested that this research strategy may narrow the scientist-practitioner gap and make it easier to demonstrate differential outcomes of different treatments.