Debraj Ray

Bio: Debraj Ray is an academic researcher from New York University. The author has contributed to research in topics: Repeated game & Population. The author has an hindex of 55, co-authored 210 publications receiving 13663 citations. Previous affiliations of Debraj Ray include Cornell University & Massachusetts Institute of Technology.

On the measurement of polarization

Abstract: Suppose that a population of individuals may be grouped according to some vector of characteristics into "clusters," such that each cluster is very "similar" in terms of the attributes of its members, but different clusters have members with very "dissimilar" attributes In that case we say that the society is polarized Our purpose is to study polarization, and to provide a theory of its measurement Our contention is that polarization, as conceptualized here, is closely related to the generation of social tensions, to the possibilities of revolution and revolt, and to the existence of social unrest in general We take special care to distinguish our theory from the theory of inequality measurement We derive measures of polarization that are easily applicable to distributions of characteristics such as income and wealth

Inequality as a Determinant of Malnutrition and Unemployment: Policy

Abstract: This paper explores the policy implications that are obtained once it is recognized that at low nutrition intakes a person's "productivity" is an increasing function of intake. In the context of a fully general equilibrium model it is shown that if aggregate assets in an economy are neither large nor small, certain patterns of Lorenz improving asset redistributions (or nutrition transfers) increase aggregate output and reduce the volume of involuntary unemployment and the incidence of undernourishment. Copyright 1987 by Royal Economic Society.

Aspirations, Poverty and Economic Change

Abstract: Some of the material here was originally presented at the World Bank Conference on Cultureand Development, June 2002, as comments on Arjun Appadurai’s paper (Appadurai (2002)).I am indebted to this paper for provoking some of the observations made here. I thank DilipMookherjee, Jonathan Morduch, Rohini Pande, and especially Srirupa Roy and Nilita Vachanifor useful comments.

Ethnicity and Conflict: An Empirical Study †

Abstract: This paper examines the impact of ethnic divisions on conict. The empirical specication is informed by a theoretical model of conict (Esteban and Ray, 2011) in which equilibrium conict is related to just three distributional indices of diversity: ethnic polarization, ethnic fractionalization, and a Greenberg-Gini index constructed across ethnic groups. Our empirical ndings verify that these distributional measures are signicant correlates of conict. The underlying theory permits us to use these results to make inferences about the relative importance of public goods in conict, as well as the extent of within-group cohesion in conictual activity. These eects are further strengthened as we introduce country-specic measures of group cohesion and the relative importance of public goods, and combine them with the distributional measures exactly as specied by the theory.

Convergence of Probability Measures

Abstract: Convergence of Probability Measures. By P. Billingsley. Chichester, Sussex, Wiley, 1968. xii, 253 p. 9 1/4“. 117s.

Greed and Grievance in Civil War

Abstract: Of the 27 major armed conflicts that occurred in 1999, all but two took place within national boundaries. As an impediment to development, internal rebellion especially hurts the world's poorest countries. What motivates civil wars? Greed or grievance? Collier and Hoeffler compare two contrasting motivations for rebellion: greed and grievance. Most rebellions are ostensibly in pursuit of a cause, supported by a narrative of grievance. But since grievance assuagement through rebellion is a public good that a government will not supply, economists predict such rebellions would be rare. Empirically, many rebellions appear to be linked to the capture of resources (such as diamonds in Angola and Sierra Leone, drugs in Colombia, and timber in Cambodia). Collier and Hoeffler set up a simple rational choice model of greed-rebellion and contrast its predictions with those of a simple grievance model. Some countries return to conflict repeatedly. Are they conflict-prone or is there a feedback effect whereby conflict generates grievance, which in turn generates further conflict? The authors show why such a feedback effect might be present in both greed-motivated and grievance rebellions. The authors' results contrast with conventional beliefs about the causes of conflict. A stylized version of conventional beliefs would be that grievance begets conflict, which begets grievance, which begets further conflict. With such a model, the only point at which to intervene is to reduce the level of objective grievance. Collier and Hoeffler's model suggests that what actually happens is that opportunities for predation (controlling primary commodity exports) cause conflict and the grievances this generates induce dias-poras to finance further conflict. The point of policy intervention here is to reduce the absolute and relative attraction of primary commodity predation and to reduce the ability of diasporas to fund rebel movements. This paper - a product of the Development Research Group - is part of a larger effort in the group to study civil war and criminal violence. For more on this effort, go to www.worldbank.org/research/conflict. Paul Collier may be contacted at pcollier@worldbank.org.

Greed and grievance in civil war

Abstract: This study investigates the causes of civil war, using a new data set of wars during 1960-99. Rebellion may be explained by atypically severe grievances, such as high inequality, a lack of political rights, or ethnic and religious divisions in society. Alternatively, it might be explained by atypical opportunities for building a rebel organization. Opportunity may be determined by access to finance, such as the scope for extortion of natural resources, and for donations from a Diaspora population. Opportunity may also depend upon factors such as geography: mountains and forests may be needed to incubate rebellion. These explanations are tested and find that opportunity provides considerably more explanatory power than grievance. Economic viability appears to be the predominant systematic explanation of rebellion. The results are robust to correction for outliers, alternative variable definition, and variations in estimation method

The microfinance promise

Abstract: In the past decade, microfinance programs have demonstrated that it is possible to lend to low-income households while maintaining high repayment rates--even without requiring collateral. The programs promise a revolution in approaches to alleviating poverty and spreading financial services, and millions of poor households are served globally. A growing body of economic theory demonstrates how new contractual forms offer a key to microfinance success--particularly the use of group-lending contracts with joint liability. For the most part, however, high repayment rates have not translated into profits, and studies of impacts on poverty yield a mixed picture. In describing emerging tensions, the paper highlights the diversity of innovative mechanisms beyond group-lending contracts, the measurement of financial sustainability, the estimation of economic and social impacts, the costs and benefits of subsidization, and the potential to reduce poverty through savings programs rather than just credit. The promise of microfinance has pushed far ahead of the evidence, and an agenda is put forward for addressing critical empirical gaps and sharpening the terms of policy discussion.