Abstract : Project IMPACT, Instructional Model/Prototypes Attainable in Computerized Training, is a comprehensive advanced development project designed to produce an effective and economical computer-administered instruction system for the Army. In this paper, the rationale for conceptualizing the instructional process in a form implementable by computer is described. The Instructional Decision Model (IDM), the heart of the CAI system, is discussed. Major issues are summarized and expectations for future model development are projected. The HumRRO hardware configuration is divided into three major subsystems: Information Processing, Data Storage and Communications. Short-range and long-range computer software development is discussed. Instructional decision making is described and illustrated. (Author)