Practitioner Review: Therapist variability, patient-reported therapeutic alliance, and clinical outcomes in adolescents undergoing mental health treatment - a systematic review and meta-analysis
Background: Previous meta-analyses have only found small correlations (r=0.10 to r=0.19) between therapeutic alliance and clinical outcomes in samples of adolescents receiving psychological therapy. Although study-level variables have been found to moderate this, little is known about the impact of therapist variability. The present meta-analysis aimed to address this gap by using patient-therapist ratio as a moderator variable. Methods: Contrary to previous reviews of adolescent alliance, individual effect sizes were extracted using a pre-registered conceptual hierarchy. Controlling for treatment-level confounds, a random effects meta-analysis assessed the moderating effect of patient-therapist ratio on the alliance-outcome relationship in pre-defined single-predictor and multi-predictor meta-regressions.Results: The alliance-outcome relationship was found to be larger than previously thought (k=28, N=2911, r=0.29, 95% Confidence Interval 0.21, 0.37;
