The Added Value of the YLS/CMI Subscales Beyond the Total Score Among Japanese Youth Offenders in Detention

This study examined whether subscales of the Youth Level of Service Case Management Inventory (YLS/CMI) have added value beyond the total score. Including 238 detained Japanese juvenile offenders (ages 16-19), the proportional reduction in mean squared error (PRMSE) method was applied. Most subscales showed added value, except for Attitudes/Orientation. For the younger group, all subscales except Attitudes/Orientation showed added value. For older juveniles, Family Circumstances/Parenting, Education/Employment, and Attitudes/Orientation did not. Construct validity was assessed via correlations with prior delinquency indicators. While the total score showed consistent associations, some subscales-notably among older youth-did not, raising concerns about their relevance. These findings suggested that subscales should be interpreted according to both statistical distinctiveness and theoretical support. Subscale analysis may aid intervention planning, particularly for younger offenders, but its utility should be judged by both psychometric and practical standards.