Are some therapists more effective when they deliver one type of therapy versus another?

Adding nuance to the between-therapist effect on patient outcomes, research has increasingly demonstrated that a given therapist can differ in their effectiveness depending on who they treat (e.g., patients with different racial/ethnic identities) and/or what they treat (e.g., patients with different presenting problems). This preregistered study examined whether individual therapists are also more or less effective depending on how they treat their patients; that is, delivering one type of therapy versus another. We did so in the context of an individual participant data meta-analysis of clinical trials that compared classes of cognitive-behavioral therapy (CBT) and psychodynamic therapy (PDT) for depression. The meta-analytic sample included 30 therapists who were crossed with treatment condition and 492 patients (M = 25.08 patients per therapist; SD = 15.77). Patients completed measures of depression at baseline and posttreatment. Multilevel structural equation models revealed significant variability in the within-therapist treatment condition–outcome association (p < .001), indicating that some therapists were more effective when delivering one treatment over the other. Descriptively, 53% of therapists had similar outcomes across both groups (ds < .20), whereas 47% had at least a small-sized treatment-type strength (ds  .20; range = 0.21–0.65). Results inform the personalization of treatment usage to the individual provider’s effectiveness data.