benefits of ridesharing in the United States was at least $7 billion a year (2015 prices). Testing Mixed-Strategy Equilibria When Players Are Heterogeneous: The Case of Penalty Kicks in Soccer (2002): Chiappori, Levitt, and Groseclose use penalty kicks from soccer games to test the idea of mixed strategies, a concept important to game theory. They do not reject the hypothesis that players choose their strategies optimally. Causes and consequences of distinctively black names (2004): Fryer and Levitt find that the rise in distinctively black names took place in the early 1970s. While previous studies found having a black name harmful, they conclude that having a distinctively black name is primarily a consequence rather than a cause of poverty and segregation. Discrimination in game shows (2004): Levitt uses contestant voting behavior on the US version of the television show Weakest Link to distinguish between taste-based discrimination and information-based discrimination theories of discrimination. Levitt found no discrimination against females or blacks, while finding taste-based discrimination against the old and information-based discrimination against Hispanics. Selected bibliography Academic publications (in chronological order) "Four essays in positive political economy" PhD Thesis, DSpace@MIT. Massachusetts Institute of Technology, Dept. of Economics, 1994. "Using Repeat Challengers to Estimate the Effect of Campaign Spending on Election Outcomes in the U.S. House." Journal of Political Economy, 1994, 102(4), pp. 777–98. "How Do Senators Vote? Disentangling the Role of Voter Preferences, Party Affiliation, and Senator Ideology." American Economic Review, 1996, 86(3), pp. 425–41. "The Effect of Prison Population Size on Crime Rates: Evidence from Prison Overcrowding Litigation." Quarterly Journal of Economics, 1996, 111(2), pp. 319–51. "The Impact of Federal Spending on House Election Outcomes." Journal of Political Economy, 1997, 105(1), pp. 30–53. (with Snyder, James M. Jr.). "Using Electoral Cycles in Police Hiring to Estimate the Effect of Police on Crime." American Economic Review, 1997, 87(3), pp. 270–90. "Measuring Positive Externalities from Unobservable Victim Precaution: An Empirical Analysis of Lojack." Quarterly Journal of Economics, 1998, 113(1), pp. 43–77 (with Ayres, Ian). "An Economic Analysis of a Drug-Selling Gang's Finances." Quarterly Journal of Economics, 2000, 115(3), pp. 755–89. (with Venkatesh, Sudhir A.). "The Impact of Legalized Abortion on Crime." Quarterly Journal of Economics, 2001, 116(2), pp. 379–420. (with Donohue, John J., III). "How Dangerous Are Drinking Drivers?" Journal of Political Economy, 2001, 109(6), pp. 1198–237. (with Porter, Jack) . "Testing Mixed-Strategy Equilibria When Players Are Heterogeneous: The Case of Penalty Kicks in