1 “A Stitch in Time: The Effects of a Novel Incentive-Based High-

Abstract: I analyze the longer-run effects of a program that pays both 11th and 12th grade students and teachers for passing scores on Advanced Placement exams. Using a difference-in-differences strategy, I find that affected students attend college in greater numbers, have improved college GPAs, and are more likely to remain in college beyond their freshman year. Moreover, the program improves college outcomes even for those students who would have enrolled in college without the program. I also find evidence of increased college graduation for black and Hispanic students ─ groups that tend to underperform in college. This evidence suggests that relatively late high-school interventions may confer lasting positive and large effects on student achievement in college, and may be effective at improving the educational outcomes of minority students. The finding of enduring benefits when extrinsic motivators are no longer provided is important in light of concerns that incentive-based-interventions may lead to undesirable practices such as “teaching-to-the-test ” and cheating