The emphasis on the deinstitutionalization of status offenders under the Juvenile Justice and Delinquency Prevention Act of 1974 included the development of programs for status offenders that would divert them from institutionalization. The system rates methodology for evaluating this effort focuses on changes in the processing of status offenders during the period of the program's operation. As a methodology, system rates provides mathematical statements about justice system behavior. The methodology calls for a series of indexes constructed at decision points in the justice system. Under this evaluation methodology, the introduction of one or more diversion programs to a system chart should permit comparison of the new system with the old one. The system rates data for the program sites were examined both collectively and by individual sites without across-site consistencies being revealed. Findings show that system rates are responsive to and portray system changes. The methodology, however, cannot determine whether system changes are the product of deinstitutionalization activities or occurred due to other factors that operated during the time frame examined. Although changes may be documented in system portraits, explanations of these changes often are not obvious. 21 tables