The methods with which Northern Illinois University (NIU) has implemented enrollment-management change and developed a more efficient enrollment-management process are noted. Some of the techniques used to better understand the admissions and demand environments and NIU's place in them are discussed to help other institutions with the uncertainties of enrollment-management. NIU's enrollment-management process changes markedly from year to year according to available resources (space, faculty, funding) and student demand. It is much easier to anticipate resource availability than student demand patterns, so NIU's methods of understanding and predicting student demand for new freshman admission are noted. The first step is forecasting the number of high school seniors in the NIU service area. The next step takes place in summer when the Institutional Research Office aids the president and provost in establishing enrollment targets for new freshmen and transfers. An enrollment simulation is performed using a Markov model, and the results give the number of new freshmen and transfers to be enrolled. Once the target for regularly-admissible students is set, attention shifts to forecasting applications, acceptances, and enrollments by ACT/high school rank combinations. To determine what can be expected from this competitive group, a Monte Carlo simulation is performed. Data on applicants and their status are updated weekly so crises do not arise from slow reaction to changes in the environment. The use of an Ad Hoc Admission/Enrollment Committee is invaluable because it hears from offices dealing directly with potential students and can anticipate changing demand patterns not reflected in numbers. (SM)