We characterize optimal honest and obedient (HO) mechanisms for the classic collective action problem with private information, where group success requires costly participation by some fraction of its members. For large n, a simple HO mechanism, the volunteer-based organization, is approximately optimal. Success is achieved in the limit with probability one or zero depending on the rate at which the required fraction declines with n. For finite n, optimal HO mechanisms provide substantial gains over unorganized groups when the success probability converges to zero, because the optimal HO success probability converges slowly and is always positive, while finite-sized unorganized groups have exactly zero probability of success.

We study the effect of hearing cases alongside female judicial colleagues on the probability that a federal judge hires a female law clerk. Federal judges are assigned to judicial panels at random and have few limitations on their choices of clerks. Using a unique dataset of federal case records merged with judicial hiring information, we find a significant effect of the fraction of copanelists who are female on a male judge’s likelihood of hiring a female clerk. This finding suggests that increases in the diversity of the upper rungs of a profession can create opportunities at the entry level.

We present a model of endogenous network formation to recover unobserved social networks using only observable outcomes. We propose a novel equilibrium concept that allows for a sharp characterization of equilibrium behaviour and that yields a unique prediction under testable conditions. While the equilibrium is characterized by a large number of non-linear equations, we show that it can be efficiently employed to recover the networks by an appropriately designed approximate Bayesian computation method. We apply the model to recover the network of social links between lawmakers in the U.S. Congress using data from the 109th to 113th legislatures. We show that social connections are important for legislators’ productivities, and we identify some of the key determinants of network centralities in the U.S. Congress.

This paper reports the first laboratory study of the swing voter's curse and provides insights on the larger theoretical and empirical literature on “pivotal voter” models. Our experiment controls for different information levels of voters, as well as the size of the electorate, the distribution of preferences and other theoretically relevant parameters. The design varies the share of partisan voters and the prior belief about a payoff relevant state of the world. Our results support the equilibrium predictions of the Feddersen-Pesendorfer model. The voters act as if they are aware of the swing voter's curse and adjust their behaviour to compensate. While the compensation is not complete and there is some heterogeneity in individual behaviour, we find that aggregate outcomes, such as efficiency, turnout and margin of victory, closely track the theoretical predictions.

We study the Markov equilibria of a model of free riding in which n infinitely lived agents choose between private consumption and irreversible contributions to a durable public good. We show that the set of equilibrium steady states converges to a unique point as depreciation converges to zero. For any level of depreciation, moreover, the highest steady state converges to the efficient level as agents become increasingly patient. These results are in contrast to the case with reversible investments, where a continuum of inefficient equilibrium steady states exists for any level of depreciation, discount factor, and size of population.

Information Aggregation and Strategic Abstention in Large Laboratory Elections by Marco Battaglini, Rebecca B. Morton and Thomas R. Palfrey. Published in volume 98, issue 2, pages 194-200 of American Economic Review, May 2008