Student retention rates are increasingly important in higher education. Higher education institutions have adopted various programs in the hopes of increasing graduation rates and grade point averages (GPAs). One of the most effective attempts at improvement has been the Supplemental Instruction (SI) program. We examined our SI program relative to three facets: attendance, attendance's influence on final scores, and graduation rates for students who had participated in these courses. These questions were also investigated focusing on specific comparison groups, as we looked into how these effects differed for minority students and nontraditional students compared with those of White and traditional peers. Overall, SI attendance led to positive outcomes--increased final course grades and graduation rates--even after adjusting for previous achievement.