2025 Zayira Ray
Julius Silver Professor, Faculty of Arts and Science,
Professor of Economics, New York University
Research Associate, NBER
Part-Time Professor, University of Warwick
Research Fellow, CESifo
Spool Member, ThReD

Department of Economics, 
New York University,
19 West 4th Street
New York, NY 10012, U.S.A.
debraj.ray@nyu.edu, +1 (212)-998-8906.

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Oxford University Press, 2008. This book is now open-access; feel free to download a copy, and to buy the print version if you like the book.
≋ Three Randomly Selected Papers
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Ethnicity and Conflict: Theory and Facts

(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).

Conveying Value Via Categories

(with Paula Onuchic), October 2019, revised December 2022. Forthcoming, Theoretical Economics.

A sender is about to come into possession of an object of heterogeneous quality. Prior to knowing that quality, she commits to a categorization. That is, she partitions the set of qualities into  subsets — some possibly singletons — and verifiably commits to reveal the element in which the quality belongs. The categories  must be monotone. Our main results fully describe the profit-maximizing categorization  for any pair of priors over object quality held by sender and receiver. We apply these results to the design of educational grades.

Inequality, Lobbying, and Resource Allocation

(with J. Esteban), American Economic Review 96, 257–279 (2006). Supplementary Notes.

Summary. This paper describes how wealth inequality may distort public resource allocation. A government seeks to allocate limited resources to productive sectors, but sectoral productivity is privately known by agents with vested interests in those sectors. They lobby the government for preferential treatment. The government—even if it honestly seeks to maximize economic efficiency—may be confounded by the possibility that both high wealth and true economic desirability create loud lobbies. Broadly speaking, both poorer economies and unequal economies display greater public misallocation. The paper warns against the conventional wisdom that this is so because such governments are more “corrupt.”