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 intosubsets — some possibly singletons — and verifiably commits to reveal the element in which the quality belongs. The categoriesmust be monotone. Our main results fully describe the profit-maximizing categorizationfor any pair of priors over object quality held by sender and receiver. We apply these results to the design of educational grades.
Summary. Agents signal their type in a principal-agent model; the principal seeks to retain good agents. Types are signaled with some ambient noise. Agents can choose to add or remove additional noise at a cost. It is shown that monotone retention strategies, in which the principal keeps the agent if the signal crosses some threshold, are generically never equilibria. The main result identifies an equilibrium with a bounded retention zone, in which the principal is wary of both excessively good and excessively bad signals: she retains the agent if the signal is “moderate” and replaces him otherwise.
Summary. We study loan enforcement in informal credit markets with multiple lenders but no sharing of credit histories, and derive the dynamics of loan size and interest rates for relational lending. In the presence of a sufficient fraction of ‘natural defaulters’, the rest of the market can be incentivized against default by micro-rationing—sharper credit limits and possibly higher interest rates that serve as gateways into new borrowing relationships. When there are too few natural defaulters in the market, this can be supplemented by macro-rationing—random exclusion of some borrowers. When information collection is endogenized, multiple equilibria may arise. (Published version of unpublished notes from 2001.)
with Rajshri Jayaraman and Francis de Vericourt, American Economic Review 106, 316-358, 2016. Online Appendix.
Summary. We study a contract change for tea pluckers. Base wages increased while incentive piece rates were lowered or kept unchanged. Yet, in the following month, output increased by 20–80%. This response contradicts the standard model, is only partly explicable by greater supervision, and appears to be “behavioral.” But in subsequent months, the increase is comprehensively reversed. Our findings suggest that behavioral responses may be ephemeral, and should ideally be tracked over an extended period.
(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 Kyle Hyndman), Review of Economic Studies74, 1125–1147, 2007.
Summary. We study coalition formation in “real time”, a situation in which coalition formation is intertwined with the ongoing receipt of payoffs. Agreements are assumed to be permanently binding: They can only be altered with the full consent of existing signatories. For characteristic function games we prove that equilibrium processes—whether or not these are history dependent—must converge to efficient absorbing states. For three-player games with externalities each player has enough veto power that a general efficiency result can be established. However, there exist four-player games in which all Markov equilibria are inefficient from every initial condition, despite the ability to write permanently binding agreements. Online Appendix.
(with Garance Genicot), Journal of Economic Theory 131, 71-100, 2006.
Summary. A single principal interacts with several agents, offering them contracts. The outside-option payoffs of the agents depend positively on how many uncontracted or “free” agents there are. We study how such a principal, unwelcome though he may be, approaches the problem of contract provision to agents when coordination failure among the latter group is explicitly ruled out. Agents cannot resist an “invasion” by the principal and hold to their best payoff. It is in this sense that “things [eventually] fall apart”.
(with Garance Genicot), Journal of Development Economics79, 398-412, 2006.
Summary. In a credit market with enforcement constraints, we study the effects of a change in the outside options of a potential defaulter on the terms of the credit contract, as well as on borrower payoffs. The results crucially depend on the allocation of “bargaining power” between the borrower and the lender. We prove that there is a crucial threshold of relative weights such that if the borrower has power that exceeds this threshold, her expected utility must go up whenever her outside options come down. But if the borrower has less power than this threshold, her expected payoff must come down with her outside options. These disparate findings within a single model permit us to interpret existing literature on credit markets in a unified way.
Summary. 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.
Summary. A principal and an agent enter into a sequence of agreements. The principal faces an interim participation constraint at each date, but can commit to the current agreement; in contrast, the agent has the opportunity to renege on the current agreement. We show that every constrained efficient sequence must, after a finite number of dates, exhibit a continuation that maximizes the agent’s payoff over all such sequences.
(with Abhijit Banerjee, Dilip Mookherjee and Kaivan Munshi), Journal of Political Economy109, 138-190, 2001.
Summary. This paper presents a theory of rent seeking within farmer cooperatives in which inequality of asset ownership affects relative control rights of different groups of members. . Predictions concerning the effect of the distribution of local landownership on sugarcane price, capacity levels, and participation rates of different classes of farmers are confirmed by data from nearly 100 sugar cooperatives in the Indian state of Maharashtra over the period 1971–93.
(with Kaoru Ueda), Journal of Economic Theory71, 324-348, 1996.
Summary. A group of agents is collectively engaged in a joint productive activity. Each agent supplies an observable input, and output is then collectively shared among the members according a social welfare function. However, individual actions are taken on a selfish basis, and the collective decision is only made after inputs are chosen. This leads to inefficiency. The aim of this paper is to show formally that, contrary to popular belief, the degree of inefficiency decreases in the extent of egalitarianism embodied in the social welfare function.
(with Anindita Mukherjee), Journal of Development Economics47, 207-239, 1995.
Summary. The co-existence of seasonal fluctuations in income and imperfect credit markets suggests that tied contracts should dominate rural labor markets. However, empirical observation from India suggests that this is far from being the case, and indeed, that there is a declining trend in labor tying. In our model, casual labor markets are always active despite the presence of seasonality, and a variety of implications are derived that link economic growth, changing information flows, and the decline of labor tying over time.
(with Anindita Mukherjee), Journal of Development Economics37, 227-264, 1992.
Summary. We model slack season wages in a village economy, in the presence of involuntary unemployment. Our model draws its inspiration from sociological notions of ‘everyday peasant resistance’. A continuum of equilibrium wage configurations is obtained. These configurations, barring one, involve wages exceeding reservation wages, despite the presence of involuntary unemployment.
(with Bhaskar Dutta and Kunal Sengupta), in P. Bardhan (ed.), The Economic Theory of Agrarian Institutions, Clarendon Press, Oxford (1989).
Summary. We study repeated principal-agent problems in which the agent can be evicted and replaced by another identical agent. Thus current output, which is perfectly observed, can be used for incentives as well as efficiency wages. We describe conditions under which eviction threats will be used in equilibrium, in addition to output-based incentives.