This study investigates the impact that different financial aid packages have on student stopout, reenrollment, and graduation probabilities. The authors simulate how various financial aid packaging regimes affect the occurrence and timing of these events. Their findings indicate that the number and duration of enrollment and stopout spells affect graduation chances. Simulations conducted indicate that the way financial aid is packaged over students' academic careers can significantly affect their stopout, reenrollment, and subsequent graduation chances. (Contains 2 figures and 5 tables.)