Stages of change in methadone maintenance: Assessing the convergent validity of two measures

This study compared 2 alternate measures of stage of change as conceived by J.O. Prochaska and C.C. DiClemente. A sample of 276 methadone maintenance patients completed both categorical and dimensional measures of stage of change regarding quitting illicit drug use. The categorical measure places participants into 1 of 5 stages based on their stated intentions regarding future illicit drug use. The University of Rhode Island Change Assessment scale (URICA) provides continuous scores on 4 stage-of-change scales. Confirmatory factor analysis was used to assess the URICA's factor structure. The relationship between URICA scores and self-reported drug use was also assessed. Comparison of the URICA and the categorical measure using discriminant function analysis indicated limited convergence between the 2 measures and suggests that they may assess different aspects of readiness to change.