We show that the design and decentralized scoring of New York's high school exit exams - the Regents Examinations - led to systematic manipulation of test scores just below important proficiency cutoffs. Exploiting a series of reforms that eliminated score manipulation, we find heterogeneous effects of test score manipulation on longer-run outcomes. While inflating a score increases the probability of a student graduating from high school by about 22 percentage points, the probability of taking advanced coursework declines by roughly 15 percentage points. There is also suggestive evidence that having a score manipulated decreases the probability of enrolling in college. We argue that these results are consistent with test score manipulation helping less advanced students on the margin of dropping out but hurting more advanced students that are not pushed to gain a solid foundation in the introductory material.