This article presents an evaluation study of a case management method for child protection services, the Delta Method for Family Supervision, in terms of supervision order duration and occurrence and duration of out-of-home placements. Additionally, case and case manager characteristics were examined. Data was collected about 224 cases, 58 case managers and 30 team managers of all 15 offices of the Child and Youth Protection Services in the Netherlands. In all cases the Delta Method was applied. Data were obtained by interviews, questionnaires and case files. Multi-level analysis was performed to study the influence of independent variables on supervision order duration, and the occurrence and duration of out-of-home placements. Case characteristics related to 87% of the differences in the duration of supervision order, case manager characteristics to 13% of the differences. Some case manager characteristics about applying the Delta Method were significantly related to shorter duration of the supervision order and the occurrence and duration of out-of-home placement. Case characteristics also showed strong relations. Together with the more general aspects of case management supported by this study, such as a one family and one worker approach, this contributes to a more effective practice of case management for child protection services.