Education and training systems are complex organizations of facilities, instructors, equipment, routines, and students. Because of this complexity, mathematical models can be used effectively to explain the behavior of educational systems and to assist in making decisions relative to better design and operation, and improved cost-effectiveness, capacity, and quality. This document, therefore, presents an assessment of the present state of the art of modeling educational systems. Important to all areas of educational research, the document is written in relatively nontechnical terms and is intended primarily for administrators who are assumed not to have strong mathematical backgrounds. A technical appendix is included for these readers who wish to pursue the actual construction of models in greater depth. (Author)