Tournaments are widely used in the economy to organize production and innovation. We study individual data on 2,775 contestants in 755 software algorithm development contests with random assignment. The performance response to added contestants varies non-monotonically across contestants of...

In Fall 2014, Wellesley College began mandating pass/fail grading for courses taken by first-year, first-semester students, although instructors continued to record letter grades. We identify the causal effect of the policy on course choice and performance, using a...