Alliance has been shown to predict treatment outcome in family-involved treatment for youth problems in several studies. However, meta-analytic research on alliance in family-involved treatment is scarce, and to date, no meta-analytic study on the alliance-outcome association in this field has paid attention to moderating variables. We included 28 studies reporting on the alliance-outcome association in 21 independent study samples of families receiving family-involved treatment for youth problems (N = 2126 families, M age youth ranging from 10.6 to 16.1). We performed three multilevel meta-analyses of the associations between three types of alliance processes and treatment outcome, and of several moderator variables. The quality of the alliance was significantly associated with treatment outcome (r = .183, p < .001). Correlations were significantly stronger when alliance scores of different measurement moments were averaged or added, when families were help-seeking rather than receiving mandated care and when studies included younger children. The correlation between alliance improvement and treatment outcome just failed to reached significance (r = .281, p = .067), and no significant correlation was found between split alliances and treatment outcome (r = .106, p = .343). However, the number of included studies reporting on alliance change scores or split alliances was small. Our findings demonstrate that alliance plays a small but significant role in the effectiveness of family-involved treatment. Future research should focus on investigating the more complex systemic aspects of alliance to gain fuller understanding of the dynamic role of alliance in working with families.
Keywords: Family-based treatment; Multilevel meta-analysis; Therapeutic alliance; Treatment outcomes; Working alliance.