- Abstract This study presents the development and psychometric properties of a five-item version of the revised Vanderbilt Therapeutic Alliance Scale (VTAS-R Short Form). A total of 255 alliance ratings, derived from therapy sessions from 86 cases of family therapy for substance-abusing adolescents, were used to generate two separate subsamples. The first subsample was used to develop the five-item form and the second subsample to estimate the measure's reliability and concurrent and predictive validity. The VTAS-R Short Form evidenced high internal consistency, was highly correlated with the full-length VTAS-R, and predicted treatment completion and adolescents’ days of cannabis use at 3 months follow-up. The findings suggest that the VTAS-R Short Form is a reliable and valid alternative to the full-length form.