Accountability in higher education most often concentrates on what and how to measure performance, but less often on how it can be used for planning, managing, and teaching. Besides serving higher education's consumers, accountability measures should also serve those who plan and manage institutions, especially those engaged in managing enrollments. Since enrollment is jointly determined by internal and external factors, the use of forecasting and simulation models can help managers determine alternative future scenarios. A three-phase model has been developed that incorporates such performance measures as enrollment forecasting and retention. In the first phase of the model, the past 25 years of a college's enrollment is "explained" in terms of internal policies related to fees and financial aid; demand-related variables, such as community demographics and economics; and supply-related variables, such as college budget, staffing, and curriculum. In the second phase, the variables used to explain enrollment are modified to forecast future enrollments, while in the third the forecast model is linked to a simulation model that uses performance measures related to enrollment management to determine the effect of specific changes. Contains 10 references. Fifteen tables showing outcomes from an implementation of the model at Arizona's Maricopa County Community College District are attached. (HAA)