Therapists differ in the amount of client progress they facilitate in psychotherapy, a phenomenon referred to as therapist effects (TEs). However, the size of TEs differs based on the characteristics of their caseloads (i.e., case-mix), treatment setting, and whether center effects are modeled with TEs. The present study estimated TEs in a specific treatment setting (university counseling centers; UCCs) and while controlling for an enhanced set of case-mix variables. A total of 43,284 clients treated by 1,486 therapists at 100 UCCs completed routine, individual psychotherapy. Therapist differences in overall effectiveness (amount of symptom change) and efficiency (speed of symptom change) were estimated with multilevel modeling while accounting for case-mix variables and center effects. Several case-mix variables accounted for portions of therapist variability in outcomes, including severity of suicidal ideation, nonrisk-related symptom severity, and prior treatment history. After controlling for case-mix and center effects, TEs of 1.85% for effectiveness and 1.67% for efficiency were found. Model-derived performance classes indicated that most therapists (near 90%) were average in effectiveness and efficiency. Despite this, the most efficient and effective therapists produced significantly better outcomes (up to 24% more symptom improvement) than their least efficient and effective counterparts. In routine practice at UCCs, therapists account for a relatively small proportion of client outcomes. However, differences between significantly above- and below-average therapists can be substantial. Examining the practices of highly effective UCC therapists may provide insight into effective psychotherapy processes and tailored recommendations for this setting. (PsycInfo Database Record (c) 2026 APA, all rights reserved).
Kilcullen et al. (Thu,) studied this question.