Implementing exportable instructional systems has always been a problem for instructional developers. Even the best instructional systems lose effectiveness when they are poorly implemented. Researchers have focused their efforts on creating mechanisms to help developers and managers improve and control implementation. However, most of these efforts do not address long-term effects, or take into account how teachers feel and react during the implementation process. This study presents the Dynamic Implementation Seeking Equilibrium (DISE) model, a nonlinear model of implementation for teacher-mediated instructional systems to measure rate of implementation over time. The DISE model's main independent variable, the exportability control factor (ECF) is an intrinsic quality of teacher-mediated instructional systems. ECF is defined as the amount of instructions, support resources, schedules of activities, and accountability methods embedded in the instructional system to delineate or control teachers' actions so they use the system according to the developers' original intent. The DISE model predicts four distinct scenarios: extinction, stable low implementation, stable high implementation, and unstable implementation with catastrophic change. Beyond the implications for the implementation of teacher-mediated instructional systems, this model offers an example of how some of the concepts, techniques, and methodologies of nonlinear dynamics can be applied to the field of instructional systems development. (Contains 21 references.) (Author/AEF)