This document reports the Center's current thinking about PPBS and data-based educational planning. In the introduction, PPBS is defined, the usual conceptualization of PPBS is outlined, current pressure to adopt PPBS in public education is discussed, and current efforts at such implementation are reviewed. The second part deals with basic concepts of a systems model and provides a detailed explication of three interrelated models. The third part relates these three systems models to PPBS, refines the original conceptualization, and provides a framework that is used in the fourth part to discuss possible innovation strategies for implementing PPBS. (DE)