Working Papers by Alessandra Casella
# | Title | Authors | Date | Length | Paper | Abstract | |
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1445 | An Experimental Study of Vote Trading | Casella, Alessandra Palfrey, Thomas R. | 12/18/2018 | 59 | sswp1445.pdf | Vote trading is believed to be ubiquitous in committees and legislatures, and yet we know very little of its properties. We return to this old question with a laboratory experiment. We posit that pairs of voters exchange votes whenever doing so is mutually advantageous. This generates trading dynamics that always converge to stable vote allocations--allocations where no further improving trades exist. The data show that stability has predictive power: vote allocations in the lab converge towards stable allocations, and individual vote holdings at the end of trading are in line with theoretical predictions. However, there is only weak support for the dynamic trading process itself. | |
1444 | Trading Votes for Votes. A Dynamic Theory | Casella, Alessandra Palfrey, Thomas R. | 12/10/2018 | 38 | sswp1444.pdf | We develop a framework to study the dynamics of vote trading over multiple binary issues. We prove that there always exists a stable allocation of votes that is reachable in a finite number of trades, for any number of voters and issues, any separable preference profile, and any restrictions on the coalitions that may form. If at every step all blocking trades are chosen with positive probability, convergence to a stable allocation occurs in finite time with probability one. If coalitions are unrestricted, the outcome of vote trading must be Pareto optimal, but unless there are three voters or two issues, it need not correspond to the Condorcet winner. If trading is farsighted, a non-empty set of stable vote allocations reachable from a starting vote allocation need not exist, and if it does exist it need not include the Condorcet winner, even in the case of two issues. | |
1408 | Trading Votes for Votes. A Decentralized Matching Algorithm | Casella, Alessandra Palfrey, Thomas R. | 10/06/2015 | 58 | SSWP_1408.pdf | Vote-trading is common practice in committees and group decision-making. Yet we know very little about its properties. Inspired by the similarity between the logic of sequential rounds of pairwise vote-trading and matching algorithms, we explore three central questions that have parallels in the matching literature: (1) Does a stable allocation of votes always exist? (2) Is it reachable through a decentralizd algorithm? (3) What welfare properties does it possess? We prove that a stable allocation exists and is always reached in a finite number of trades, for any number of voters and issues, for any separable preferences, and for any rule on how trades are prioritized. Its welfare properties however, are guaranteed to be desirable only under specific conditions. A laboratory experiment confirms that stability has predictive power on the vote allocation achieved via sequential pairwise trades, but lends only weak support to the dynamic algorithm itself. | |
1359 | Vote Trading with and without Party Leaders | Casella, Alessandra Palfrey, Thomas R. Turban, Sebastien | 01/31/2012 | sswp1359.pdf | |||
1331 | Competitive equillibrium in markets for votes (revised) | Casella, Alessandra Llorente-Saguer, Aniol Palfrey, Thomas R. | 02/23/2012 | sswp1331R2.pdf | |||
1261 | Minorities and storable votes | Casella, Alessandra Palfrey, Thomas R. Riezman, Raymond G. | 12/01/2006 | 48 pages | sswp1261R.pdf | ||
1173 | An Experimental Study of Storable Votes | Casella, Alessandra Gelman, Andrew Palfrey, Thomas R. | 09/01/2003 | 69 pages | wp1173.pdf | The storable votes mechanism is a method of voting for committees that meet periodically to consider a series of binary decisions. Each member is allocated a fixed budget of votes to be cast as desired over the multiple decisions. Voters are induced to spend more votes on those decisions that matter to them most, shifting the ex ante probability of winning away from decisions they value less and towards decisions they value more, typically generating welfare gains over standard majority voting with non-storable votes. The equilibrium strategies have a very intuitive feature the number of votes cast must be monotonic in the voter's intensity of preferences but are otherwise difficult to calculate, raising questions of practical implementation. In our experiments, realized efficiency levels were remarkably close to theoretical equilibrium predictions, while subjects adopted monotonic but off-equilibrium strategies. We are lead to conclude that concerns about the complexity of the game may have limited practical relevance. |