We study a multi-dimensional collective decision under incomplete information. With votes taken by simple majority in each dimension, the outcome is the coordinate-wise median. But, judicious rotations of the orthogonal axes - the dimensions, or issues that are voted upon - lead to welfare improvements. Such rotations cover the entire set of anonymous, Pareto efficient and dominant strategy incentive compatible mechanisms in our environment (Kim and Rousch (1984) and Peters et. al (1992)).

We extend Kreps and Wilson's 1982 definition of sequential equilibrium to multi-stage games with infinite sets of signals and actions. We define “broad sequential epsilon-equilibria” by properties of “sequential epsilon-rationality” and “broad consistency.” Given beliefs, a player's strategy is sequentially epsilon-rational if, at every date t, at every possible signal outside a uniformly unlikely set, the player cannot expect to gain more than epsilon by any feasible deviation.

We consider a decision maker with recursive utility, as formalized by Epstein and Zin (1989). We show that, as this decision maker  becomes more patient, his ranking of conditionally i.i.d. processes is approximately that of an expected utility decision maker.

We consider two-player repeated games, where the players observe their own payoffs with a positive probability. Typically, a player observes neither the other's actions nor her payoff.  We show that knowing her own payoff is sufficient to obtain any strictly efficient payoff  by sequential equilibrium, when costly communication is available and the players are  sufficiently patient.

For a constant ε>0, we prove a poly(N) lower bound on the (randomized) communication complexity of ε-Nash equilibrium in two-player N×N games.For n-player binary-action games we prove an exp(n) lower bound for the (randomized) communication complexity of (ε,ε)-weak approximateNash equilibrium, which is a profile of mixed actions such that at least (1-ε)-fraction of the players are ε-best replying. 

Risks related to events that arrive randomly play important role in many real life decisions, and models of learning and experimentation based on two-armed Poisson bandits addressed several important aspects related to strategic and motivational learning in cases when events arrive at jumps times of the standard Poisson process. At the same time, these models remain mostly abstract theoretical models with few direct economic applications.

A long-standing tradition models legal enforcement as being distinct from community enforcement, whereby individuals follow the law because legal enforcement constrains the actions that players may take or fixes their payoffs from their actions.

We provide an axiomatic characterization of an income segregation index in school districts. One axiom requires that single-school districts be the least segregated of all districts. A second axiom requires that any reorganization of a subdistrict that raises its segregation, raises the districtwide segregation as well. A third axiom requires an intuitive decomposition by subdistricts into within-district and between-district terms.

Koszegi and Rabin’s (2006, 2007, 2009) model of expectations-based reference-dependent preferences offers a unified explanation for a diverse body of evidence across different domains. However, almost a decade of direct lab tests of the model has generated mixed evidence: in only a subset of (what appear to be) similar experimental setups are lagged-probability-beliefs treatments found to affect behavior as (apparently) predicted by the theory. The present paper aims to investigate why.

Online reviews could, in principle, greatly improve the match between consumers and products. However, the authenticity of online user reviews remains a concern; firms have an incentive to manufacture positive reviews for their own products and negative reviews for their rivals. In this paper, we marry the diverse literature on economic subterfuge with the literature on organizational form. We undertake an empirical analysis of promotional reviews, examining both the extent to which fakery occurs and the market conditions that encourage or discourage promotional reviewing activity.

Two  firms produce substitute goods with unknown quality. At each stage the firms set prices and a consumer with private information and unit demand buys from one of the fi rms. Both  firms and consumers see the entire history of prices and purchases. Will such markets aggregate information? Will the superior  rm necessarily prevail? We adapt the classical social learning model by introducing strategic dynamic pricing. We provide necessary and sufficient conditions for learning. In contrast to previous results, learning can occur when signals are bounded.

We study a discounted repeated inspection game with two agents and one principal. Both agents may profit by violating certain rules, while the principal can inspect on at most one agent in each period, inflicting a punishment on an agent who is caught violating the rules. The goal of the principal is to minimize the discounted number of violations, and he has a Stackelberg leader advantage. We characterize the principal's optimal inspection strategy.

We prove that every multiplayer quitting game admits a sunspot epsilon-equilibrium for every epsilon > 0, that is, an epsilon-equilibrium in an extended game in which the players observe a public signal at every stage. We also prove that if a certain matrix that is derived from the payoff s in the game is a Q-matrix in the sense of linear complementarity problems, then the game admits a Nash epsilon-equilibrium for every epsilon > 0.