The alliance-outcome association in group interventions: A multilevel meta-analysis.

Objective: The therapeutic alliance has been studied in group interventions, but its relationship to patient outcome is still controversial. This study systematically reviewed the association of both the member-leader and member-group alliance with patient outcomes, and assessed the effects of several theoretically informed moderators. Method: A three-level meta-analysis was conducted on 57 studies to disentangle within- and between-study variability in the alliance-outcome association. Results: The overall effect size of the unconditional model was r = -.259 (95% CI: -.302, -.214; p < .001), whereas the correlation between alliance and outcome based on the three-level meta-analytic mode…