Do therapists vary much in their success? Findings from four outcome studies.

Success rates of psychotherapists were compared across each of four treatment outcome studies, with results indicating: considerable difference between therapists in their average success rates; considerable variability in outcome within the caseload of individual therapists; little support for the widely held view that certain therapists are best for certain kinds of patients; and variations in success rate typically have more to do with the therapist than with the type of treatment.