Spending on big-time college athletics is often justified on the grounds that athletic success attracts students and raises donations. We exploit data on bookmaker spreads to estimate the probability of winning each game for college football teams. We then condition on these probabilities using a propensity score design to estimate the effects of winning on donations, applications, and enrollment. The resulting estimates represent causal effects under the assumption that, conditional on bookmaker spreads, winning is uncorrelated with potential outcomes. We find that winning reduces acceptance rates and increases donations, applications, academic reputation, in-state enrollment, and incoming SAT scores.

Public transit accounts for 1 percent of US passenger miles traveled but attracts strong public support. Using a simple choice model, we predict that transit riders are likely to be individuals who commute along routes with severe roadway delays. These individuals' choices thus have high marginal impacts on congestion. We test this prediction with data from a strike in 2003 by Los Angeles transit workers. Estimating a regression discontinuity design, we find that average highway delay increases 47 percent when transit service ceases. We find that the net benefits of transit systems appear to be much larger than previously believed. (JEL H76, J52, L92, R41)

Many believe that classroom interactions play an important role in students’ academic achievement, but there is little evidence on peer effects within subclassroom groups. We exploit random seat assignment in a Chinese middle school to estimate how the gender of neighboring students affects a student’s academic achievement. We find that being surrounded by five females rather than five males increases a female’s test scores by 0.2–0.3 standard deviations but has no significant effects on a male’s test scores. These results suggest a low-cost way to potentially improve performance within the world’s largest school system.

Previous studies of the effect of ridesharing on traffic fatalities have yielded inconsistent conclusions. We revisit this question using proprietary data from Uber measuring monthly rideshare activity at the Census tract level. We find a consistent negative effect of ridesharing on traffic fatalities, with impacts concentrated during nights and weekends. Our results imply that ridesharing has decreased U.S. traffic fatalities by 5.2% in areas where it operates. The annual life-saving benefits are $6.8 billion. Back-of-the-envelope calculations suggest that these benefits are of similar magnitude to producer surplus captured by Uber shareholders or consumer surplus captured by Uber riders.

Health insurance affects the rate at which individuals visit hospitals and emergency departments (EDs). We identify the causal effect of losing health insurance using a regression discontinuity design. We compare individuals just before and after their twenty third birthday, which insurers have used as a cutoff after which students are no longer eligible for their parents' health insurance: 1.5% of young adults lose their health insurance upon turning 23, and this transition leads to a 1.6% decrease in ED visits and a 0.8% decrease in hospital stays. We discuss why these estimates are larger than those observed among teenage populations.