Strotz (1956) and Pollak (1968) were among the first to study the behaviour of an economic agent whose preferences change over time. They suggested that such an agent would choose a “consistent plan” which they described as “the best plan that he would actually follow”. A Markov-consistent plan has a particularly simple structure: current decisions are independent of past decisions, except insofar as past decisions affect the current values of state variables. Unfortunately, Markov-consistent plans do not generally exist. In this paper, we demonstrate that the existence problem dissappears for finite horizon problems when one introduces even a small amount of smooth uncertainty into production.

In this paper we study a behavioral model of conflict that provides a basis for choosing certain indices of dispersion as indicators for conflict. We show that a suitable monotone transform of the equilibrium level of conflict can be proxied by a linear function of the Gini coefficient, the Herfindahl-Hirschman fractionalization index, and a specific measure of polarization due to Esteban and Ray. (JEL D31, D63, D74)

A classical theme in social analysis views economic class divisions as the main cause of social conflict. Yet many, if not most of the conflicts we observe today appear to be ethnic in nature. It appears that the "vertical" nature of class divisions is often dominated by the "horizontal" antagonisms across groups delineated by noneconomic markers. This paper highlights the perverse synergy of economic inequality within ethnic groups, and its role in the salience of ethnic conflict. In a model of group formation which allows both class and ethnic groupings to emerge, we show that ethnic, as opposed to class, conflict may be focal, and precisely in the presence of economic inequality. (JEL D72, D74)

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.”

Economic inequality is of interest not only at some intrinsic level, but also for its close connections to diverse variables, ranging from economic indicators such as growth rates to sociopolitical outcomes such as collective action and conflict.It is only natural, then, to study the evolution of inequality in an economic system.It is fair to say that the dominant view on this topic is that inequality is the outcome of a constant battle between convergence and "luck" (Gary Becker and Nigel Tomes, 1979).Current asset inequalities may echo into the future, but their natural tendency is to die out (owing to a convex investment technology).Disparities are only sustained through ongoing stochastic shocks (see also David Champernowne, 1953;Glenn Loury, 1981).A second approach emphasizes that initial conditions determine final outcomes, owing principally to a nonconvex investment technology (see e.g.

Can historical wealth distributions affect long-run output and inequality despite “rational” saving, convex technology and no externalities? We consider a model of equilibrium short-period financial contracts, where poor agents face credit constraints owing to moral hazard and limited liability. If agents have no bargaining power, poor agents have no incentive to save: poverty traps emerge and agents are polarized into two classes, with no interclass mobility. If instead agents have all the bargaining power, strong saving incentives are generated: the wealth of poor and rich agents alike drift upward indefinitely and “history” does not matter eventually.

Suppose that the authors are interested in the distribution of a set of characteristics over a population. They study a precise sense in which this distribution can be said to be polarized and provide a theory of measurement. 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. The authors take special care to distinguish their theory from the theory of inequality measurement. They derive measures of polarization that are easily applicable to distributions of characteristics such as income and wealth. Copyright 1994 by The Econometric Society.

We model intergroup conflict driven by economic changes within groups. We show that if group incomes are low, increasing group incomes raises violence against that group and lowers violence generated by it. We then apply the model to data on Hindu-Muslim violence in India. Our main result is that an increase in per capita Muslim expenditures generates a large and significant increase in future religious conflict. An increase in Hindu expenditures has a negative or no effect. These findings speak to the origins of Hindu-Muslim violence in post-Independence India.

We develop the measurement theory of polarization for the case in which income distributions can be described using density functions. The main theorem uniquely characterizes a class of polarization measures that fits into what we call the “identity-alienation” framework, and simultanously satisfies a set of axioms. Second, we provide sample estimators of population polarization indices that can be used to compare polarization across time or entities. Distribution-free statistical inference results are also used in order to ensure that the orderings of polarization across entities are not simply due to sampling noise. An illustration of the use of these tools using data from 21 countries shows that polarization and inequality orderings can often differ in practice.

Putnam defines social capital as “features of social organization, such as networks, norms and social trust that facilitate coordination and cooperation ” (Putnam 1995: 67). Social networks are typically associated with social trust and with norms that promote coordination and cooperation for mutual benefit. Strong ties between individuals, infused with norms of reciprocity and trust, are often thought to help cooperation among them. They would enable these groups and society as a whole to deal smoothly and effectively with multiple social and economic issue. Other authors have noted that, in different contexts, strongly bonded groups may have adverse consequences for others (such as Portes and Landolt (1996)) or for themselves (see for instance Akerlof (1976) or Basu (1986)). Based on our earlier work on risk sharing in groups and networks (Genicot and