PPRNet Clinical summary: Is the Amount of Therapist Training Related to Client Outcomes?

Therapists account for about 8.2% of patient outcomes – that is, some therapists are reliably more effective than others, and an 8.2% impact is not trivial. But is it true that as therapists advance through training and gain experience, they become more skilled, which improves their patients’ outcomes? Research in this area has yielded mixed or contradictory results. Some studies suggest that more therapist training leads to better outcomes, while other studies indicate that training and outcomes are minimally related or unrelated. However, this research area has been marked by significant methodological and conceptual problems. Most of the research tends to use cross-sectional research designs (e.g., comparing therapists at different levels of training but not measuring the cumulative effect of training across time), sometimes it fails to use appropriate data analysis (mixing up unique within-therapist experience and client outcomes with average between-therapist experience and outcomes), and it often conceptualizes therapist experience in ways that muddy an already complex construct (e.g., by defining experience in different ways such as the mere passage of time, or the number of clients seen, or time spent in direct client contact and/or supervision). In this study, Zumbul and Kivlighan examined 192 clients treated by 45 doctoral-level therapist trainees at various stages of their training who received intensive clinical supervision. They measured therapist experience as the number of hours trainees had spent with clients and in supervision – a more direct indication of experience. Client outcomes were assessed every 8 weeks using a standardized distress measure. The data were longitudinal (client outcomes and therapist experience were measured across time), not cross-sectional. And the researchers used modern data analysis to separate unique within-therapist experience and clients’ outcomes from the average therapist experience and client outcome. When therapist trainees’ hours of direct experience were higher than average, clients showed a greater reduction in distress. Perhaps the most interesting finding was that higher levels of therapist experience were most impactful in producing better outcomes for those clients who were more distressed. For clients with lower levels of distress, the amount of therapist trainee experience was not as important.

Practice Implications 

In the past, the psychotherapy field was perplexed by research indicating that more therapist training does not always translate into better patient outcomes. But this research area has been troubled by several problems, leading to contradictory and counterintuitive findings. In this study, the authors did a good job of addressing some of these problems and found that the amount of psychotherapy training matters, especially for clients with higher initial levels of distress. More distressed clients may require more nuanced therapeutic interventions that therapists with more experience and training can deliver effectively. Clients with lower levels of distress may do just as well with a therapist with less training and experience.

Zumbul, S., & Kivlighan, D. M., Jr. (2026). Therapist trainee experience and client outcome: A within-person analysis of hours of experience, client order, initial client distress, and treatment length. Psychotherapy. Advance online publication. https://dx.doi.org/10.1037/pst0000612