Focus on therapeutic alliance: The psychometric properties of six measures across three treatments

The psychometric properties of six measures of therapeutic alliance (California Psychotherapy Alliance Scales; Penn Helping Alliance Rating Scale; Vanderbilt Therapeutic Alliance Scale; and the Working Alliance Inventory-therapist, client, and rater versions) were compared in a sample of substance-dependent individuals participating in a randomized clinical trial of three psychotherapies. Internal consistency, interrater reliability, and intercorrelations among the instruments were evaluated. Results supported the construct validity of the therapeutic alliance and indicated that all six measures had acceptable reliabilities. Correlations between observer and participant measures were comparatively low. Reliabilities did vary, however, by treatment condition, suggesting that psychometric properties, and by extension alliance-process-outcome relationships, may vary across treatments.