The Program of Research and Evaluation for Public Schools (PREPS) model is unique because all research and evaluation activities are conceived, conducted, and controlled by the local public schools, members of the consortium. It is a delivery system designed to improve school effectiveness. PREPS was developed as a result of the demand for school accountability. Public school superintendents sought the assistance of the College of Education (COE) at Mississippi State University (MSU) to embark on a joint venture to provide sound data for making curricular changes. PREPS was designed to provide research and evaluation services to member schools. The consortium became an independent incorporated entity in 1984, capable of contracting as PREPS, Inc. The model has stressed utilization and application of evaluation results. The criteria for judging an evaluation model include practicality; manipulable components; economy of use; easily communicable components; comprehensiveness; synergism; phase flexibility; allowance of differential resource investment in components; recognition of influence on balance of system caused by the change process; flexible and versatile application to different organizational structures; provisions for evaluation, effectiveness, and impact assessment of change; and recognition of the humanity of participants. The interaction of MSU/COE and public schools has been mutually beneficial. (DWH)