Research

Publications


We study an election under the influence of an interest group, assuming that a committee must decide between two options -- to implement a reform or to stay with the status quo -- and that all its members are aligned and in favor of the reform. The decision is taken via simultaneous voting and simple majority. An interest group that prefers the status quo offers an equal share of a ''small'' budget to any member that votes for against the reform. We demonstrate that even if the available budget is a miniscule fragment of the one required to buy the election for sure (Dal Bò, 2007), the interest group can be quite disruptive: there is always a completely mixed equilibrium in which the status quo is the most likely outcome, and the probability of its implementation converges to one as the size of the committee increases. The strategic uncertainty generated by the fact that other equilibria also exist, in which the reform is the most likely winner, seems to be the price that the interest group pays when attempting to buy an election for peanuts. We study the model under different assumptions on how the voting stage proceeds, but concerns on democratic quality do not vanish. 


In the multiple-partners job market, introduced in (Sotomayor, 1992), each firm can hire several workers and each worker can be hired by several firms, up to a given quota. We show that, in contrast to what happens in the simple assignment game, in this extension, the firms-optimal stable rules are neither valuation monotonic nor pairwise monotonic. However, we show that the firms-optimal stable rules satisfy a weaker property, what we call firm-covariance, and that this property characterizes these rules among all stable rules. This property allows us to shed some light on how firms can (and cannot) manipulate the firms-optimal stable rules. In particular, we show that firms cannot manipulate them by constantly over-reporting their valuations. Analogous results hold when focusing on the workers. Finally, we extend to the multiple-partners market a known characterization of the fair-division rules on the domain of simple assignment games.

Working Papers


When truth-seeking agents take turns and vote sequentially on a binary issue (e.g. support a reform, oppose it, or abstain), they can base their decisions both on their private information and on the actions taken by others before them. As we show, this allows the group not only to aggregate information more effectively than if votes were cast simultaneously, but, perhaps surprisingly, to achieve the highest possible efficiency level (i.e. to reach full information equivalence) even when voters differ in the precision of the information they possess. 


We examine the impact of deliberation on political learning and election outcomes. We model a rational, common-valued electorate voting between two alternatives under majority rule, after potentially acquiring costly private information and sharing it freely through public deliberation. Deliberation can lead to free-riding on information gathering and encourage the emergence of informed political experts. But deliberation may also legitimize purely electoral outcomes---we provide conditions under which the same equilibrium without deliberation can be an equilibrium with deliberation---and may yield more accurate decisions. However, deliberation may also reduce electoral accuracy. Our results contribute to the understanding of the strengths and limitations of deliberative democracies, both from a normative and a positive perspective. 

Work in Progress


Parties have been increasingly polarizing and spending in recent decades. How does this link with turnout? What is the role of mobilization and persuasion technologies? We study the effect of changes in technologies of mobilization (make people vote) and targeting (make people vote for me).


We study a situation in which voters must decide whether to implement or not a reform. However, they are imperfectly informed about the adequacy of the reform, and they only get to see (individually) a signal about it before casting their vote. We show that if one of the alternatives is susceptible to not be implemented even if it wins the election, close elections might arise, which gives rise to aggregate uncertainty potentially playing a crucial role in the final outcome.


We study ex-post implementability of social rules in a framework that accounts for interdependent values.  In this setting, voters' ideal point is determined by a convex combination of their own private signal and a function of the other signals. We show that any ex-post implementable social choice rule that depends only on voters' ideal points must be a Generalized Median Rule.