An examination of therapists' professional characteristics as moderators of the effect of feedback on psychological treatment outcomes.

Feedback-informed treatment (FIT) has been shown to reduce the gap between more and less effective therapists. This study aimed to examine therapists' professional characteristics as potential moderators of the effect of feedback on treatment outcomes.

The IAPT-FIT Trial was a clinical trial where therapists were randomly assigned to a FIT group or a usual care control group. Treatment response was monitored using measures of depression (PHQ-9), anxiety (GAD-7) and functional impairment (WSAS). In a secondary analysis of this trial (n = 1,835 patients; t = 67 therapists), we used multilevel modelling to examine interactions between therapists' professional characteristics (e.g., attitude towards and self-efficacy regarding feedback utilization, decision-making style, job satisfaction, burnout, difficulties in practice, coping styles, caseload size) with random allocation (FIT vs. controls) to identify moderators of the effects of feedback.

Between 9.6% and 10.8% of variability in treatment outcomes was attributable to therapist effects. Therapist-level caseload sizes and external feedback propensity (EFP) moderated the effect of feedback on depression outcomes. No statistically significant main effects were found for any of the included therapist characteristics.

FIT reduced variability in outcomes between therapists and was particularly effective for therapists with high EFP and larger caseloads.