Based on a doctoral dissertation that involved a study of the nation's 100 most successful school computer systems, this report summarizes the study's purpose, scope, methodology, resultant model, general observations, and future implications. The model is divided into two major sections: (1) strategic planning activities, focusing on computer system inputs; and (2) tactical planning activities, discussing computer system processes, outputs, and feedback. Questionnaires were submitted to 75 school districts nominated for their outstanding administrative computer systems and 50 districts nominated for their outstanding instructional computer systems. Responses from 100 (80 percent) of the school districts cited useful concepts and practices. Telephone interviews with 24 survey respondents augmented the questionnaire data. Focused on the design of microcomputer and minicomputer systems, the model guides the design of inhouse computer systems for both administrative and instructional applications. Step-by-step procedures outline the key concepts of the study: that planning is a central element of the computer design process at all stages, and that user involvement should be pervasive through the planning, implementation, and growth of the computer system. (MLF)