Thirty-three of the 39 jurisdictions which reported having objective inmate classification systems responded to a survey regarding the development, implementation, and evaluation of their classification systems. Survey data were supplemented by interviews during site visits to eight agencies. An indepth assessment of the effectiveness of the objective classification systems of California, Illinois, and Wisconsin was conducted. Information on development and implementation suggests that the goals and objectives for the system should be identified early in the project, and the agency director and top level staff must be committed to the project. Most respondents found that the adaptation of an existing system was more efficient than designing a completely new system. The implementation plan should include pilot testing of the system, accompanied by written policies and procedures. The training of personnel at all levels is crucial to the system's effective implementation. Evaluation has revealed sufficient benefits from objective classification systems to warrant their continued development and use. In the three jurisdictions whose systems were assessed indepth, the proportion of inmates housed in lower security levels has increased without adversely affecting misconduct rates. 32 figures, 67 tables, 70 references, and appended study instruments and methodological information.