Sex ratios, i.e., relative numbers of men and women, can affect marriage prospects, labor force participation, and other social and economic variables. But the observed association between sex ratios and social and economic conditions may be confounded by omitted variables and reverse causality....

This paper shows that the presence of different types of players { those who only care abouttheir own material payoffs and those who reciprocate others' contributions { can explain the robustfeatures of observed contribution patterns in public good contribution games, even without thepresence of...

"In Fall 2009, officials from Chicago Public Schools changed their assignment mechanism for coveted spots at selective college preparatory high schools midstream. After asking about 14,000 applicants to submit their preferences for schools under one mechanism, the district asked them re-submit...