A generalizability theory analysis of group process ratings in the treatment of cocaine dependence

Videotaped group drug counseling sessions were rated for alliance, self-disclosure, positive and negative feedback, group cohesion, and degree of participation of each group member. Interrater reliability was good to excellent for most measures. However, generalizability coefficients based on statistical models that included terms for patient, counselor, session, group, and rater revealed that some measures had inadequate dependability at the patient level if only two raters and two sessions were used to create patient-level scores. In contrast, good generalizability coefficients based on two raters and two sessions were obtained for alliance, non-positive learning statements received from counselor, participation variables, and self-disclosures about the past. The implications of the findings for the design of process-outcome studies are discussed.