(with Rajiv Sethi), Journal of Public Economic Theory 12, 399-406, 2010.
Summary. Elite educational institutions have turned to criteria that meet diversity goals without being formally contingent on applicant identity. Under weak and generic conditions, such color-blind affirmative action policies must be nonmonotone in student test scores.
(with Rajiv Vohra) Econometrica 87(5), 1763–1779 Online Appendix.
Summary. The stable set of von Neumann and Morgenstern can be extended to cover farsighted coalitional deviations, as proposed by Harsanyi (1974), and more recently reformulated by Ray and Vohra (2015). However, while coalitional deviations improve on existing outcomes, coalitions might do even better by moving elsewhere. Or other coalitions might intervene to impose their favored moves. We show that every farsighted stable set satisfying some reasonable, and easily verifiable, properties is unaffected by the imposition of this stringent maximality requirement.
(with Joan Esteban and Laura Mayoral), Science 336, 858 – 865, 2012.
Summary. Over the second half of the 20th century, conflicts within national boundaries became increasingly dominant. Many (if not most) such conflicts involved violence along ethnic lines. On the basis of recent theoretical and empirical research, we provide evidence that preexisting ethnic divisions do influence social conflict. Our analysis also points to particular channels of influence. Specifically, we show that two different measures of ethnic division—polarization and fractionalization—jointly influence conflict, the former more so when the winners enjoy a “public” prize (such as political power or religious hegemony), the latter more so when the prize is “private” (such as looted resources, government subsidies, or infrastructures).