The initial phase of this study consisted of separate mail surveys to CPS and police agencies in late 1991 and early 1992; a total of 325 municipal police agencies, 279 county law enforcement agencies, and 239 child welfare agencies responded. In the second phase of the study, seven counties were selected for case studies, based on survey results, personal recommendations, program variability, and the potential for serving as model joint-investigation programs. Results of the national surveys and case studies were used to develop guidelines for model joint investigation programs. These models offer a general description of each program, describe various program elements, and provide basic enhanced program options. Program model 1 uses improved agency-based joint investigations with existing agency resources. Under this model, joint child abuse investigations are handled by specialized investigative units of police or sheriffs' departments, CPS investigators, and assigned district attorneys, using written protocols. Investigators use existing facilities -- schools, hospitals, police stations, or CPS offices, for example -- to interview alleged victims. Program model 2 uses all of the program elements in the agency-based approach, except that specialized multidisciplinary interview centers are used to conduct child-victim interviews and develop investigation strategies. Program model 3, the Child Advocacy Center (CAC) model, involves independent multidisciplinary programs designed to facilitate joint investigations of reported child abuse, reduce the trauma of repeated victim interviews, and initiate victim therapy. 36 references and a listing of joint investigation training resources