Psychometric properties of the contingency management competence scale

Contingency management (CM) is an evidence-based treatment, and clinicians are beginning to implement this intervention in practice. However, little research exists on methods for assuring appropriate implementation of CM. This study describes the development and psychometric properties of the 12-item CM Competence Scale (CMCS). Thirty-five therapists from nine community-based clinics participated; following a training period, a randomized trial evaluated the efficacy of CM in cocaine abusing patients. Analyses of the CMCS are based on ratings from 1613 audiotapes of therapist interactions with 78 patients enrolled in the training phase and 103 patients in the randomized phase. Inter-rater reliability from 11 raters and internal consistency of items on the CMCS was good to excellent. Items loaded onto two factors: one contained items specific to discussions of the outcomes of urine testing and reinforcement, and the other contained general items related to use of praise, communication of confidence, empathy, skillfulness, and maintaining session structure, as well as discussions of self-reports of drug use when they occurred. During the training phase in CM delivery, scores on the CMCS rose significantly between earlier and later training sessions, and during the randomized phase, CM sessions were rated more highly than non-CM sessions. Scores on the subscale assessing general items were significantly correlated with indices of the therapeutic alliance and predictive of durations of cocaine abstinence achieved. These data suggest that the CMCS is reliable and valid in assessing delivery of CM and that competence in CM delivery is associated with improved patient outcomes.