Access to higher education in the United States is increasingly on the public policy agenda as funding constraints affect the realization of college attendance for many middle and low-income students. We use the Pell Grant as a proxy for low-income participation, and the percent of undergraduate students receiving a Pell Grant (Pell Prevalence Ratio, or "PPR") in 2003-04 at 846 public and private universities as the variable of interest to address two questions. First, what factors contribute to the variation among universities in their PPR? Second, to what extent does an institution's actual PPR deviate from the PPR estimated from our empirical model? (Contains 1 figure, 4 tables and 6 footnotes.)