Described here is Project 12-Ways, a large service project employing an ecobehavioral approach to the treatment and prevention of child abuse and neglect. By ecobehavioral it is meant that multifaceted in-home services are provided to clients, and that in-home data are collected on as many variables related to these services as possible. Four levels of research, data collection, and assessment are used to evaluate these services: Included here is a discussion of these levels of assessment. They are: data collected for clinical purposes; data from single-case experiments; research through the use of single-subject design logic applied to several subjects or groups of subjects, or by group statistical research designs; and program evaluation. The particular focus here is the program evaluation data which compare incidents of abuse and neglect during and after treatment between 50 families served by Project 12-Ways and 47 comparison protective service families. The data showed significantly fewer combined abuse and neglect incidents among the families served by Project 12-Ways. Suggestions for additional program evaluation data are provided along with a discussion of the limitations of the current analysis.