The Psychotherapist Matters: Comparison of Outcomes Across Twenty-Two Therapists and Seven Patient Samples


Address correspondence to Dr. Lester Luborsky, 514 Spruce St., Philadelphia, PA, 19106.


This research relies on a useful focus for finding the contribution of the psychotherapist to the outcome of the treatment: the outcomes of each therapist's caseload. Our data consist of 22 therapists' caseloads within seven samples of drug-addicted and depressed patients. We concluded that (a) there were important differences in the improvement levels and post-treatment outcomes of patient caseloads among the therapists sampled, and (b) these differences in improvement could not be explained by differences in patient background or severity. Some of the differences appeared to reflect the therapists' efficacy with their patients because (a) a unique feature of the design was that three therapists took part in more than one study and therefore more than one caseload; these three therapists showed a similar efficacy in each new caseload, (b) At this time, it may be that the safest basis for choosing therapists for research studies or for clinical purposes is their “work sample” record of efficacy with their previous caseloads.