An empirical approach is taken to the problem of predicting effects of student financial aid programs on postsecondary enrollment rates and patterns. A model of students' enrollment decisions is developed and used to estimate the likely effects of alternative award policies for the Basic Educational Opportunity Grant (BEOG) program. The analysis is based on data from the National Longitudinal Study of the High School Class of 1972. The empirical approach provides a means for analyzing individuals' choices among a finite number of mutually exclusive alternatives and may be of interest to researchers dealing with problems of that type in education or elsewhere. The model can be applied to analyses of a wide variety of student financial aid policies at the state or federal level. The results are addressed to federal policymakers and others concerned with the consequences of BEOG award policies for students and for institutions. (Author/MSE)