On the Optimal Majority Rule (original) (raw)
Related papers
Constitutional Political Economy, 2006
This note studies the volatility of the policy chosen by a committee whose members' preferences are volatile, due to common and individual preferences shocks. It is shown that majority voting mitigates the latter but not the former. The volatility of the policy is smaller the smaller the volatility of members' preferences, smaller the larger the size of the committee, and smaller than if it was chosen by a single member. The results hold in a context of uncertainty and with multidimensional issues.
Journal of Economics, 2012
We analyze the voting behavior of a small committee that has to approve or reject a project proposal whose return is uncertain. Members have diverse preferences: some of them want to maximize the expected value, while others have a bias towards project approval and ignore their information on the project value. We focus on the most efficient use of scarce information when members cannot communicate prior to voting, and we provide insights on the optimal composition of the committee. Our main result is that the presence of biased members can improve the voting outcome, by simplifying the strategies of unbiased members. Thus, committees with diverse members perform as well as homogeneous committees, and even better in some cases. In particular, when value-maximizing members outnumber biased members by one vote, the optimal equilibrium becomes unique.
Bargaining in committees of representatives: the optimal voting rule
Committees are often made up of representatives of different-sized groups of individuals, and make decisions by means of a voting rule which specifies what vote configurations can pass a decision. This raises the question of the choice of the optimal voting rule, given the different sizes of the groups that members represent. In this paper we take a new departure to address this problem, assuming that the committee is a bargaining scenario in which negotiations take place 'in the shadow of the voting rule' in search of unanimous consensus. That is, a general agreement is looked for, but any winning coalition can enforce an agreement.
An experimental study of the efficiency of unanimity rule and majority rule
Public Choice, 2014
We test several claims about the relationship between unanimity rule and Pareto optimality. Tullock (1962), Mueller (2003), and other scholars argue that unanimity rule is more capable of producing Pareto optimal outcomes than other voting rules, such as majority rule, because unanimity rule passes an alternative only if it makes everyone better off. Majority rule can pass alternatives that make some individuals worse off. , in contrast, claim that majority rule is at least as likely to select Pareto optimal outcomes as unanimity rule in finite games if proposals are random, sincere, or strategic. We test the two sets of conjectures in a two dimensional framework using laboratory experiments. Our results suggest: 1) majority rule enters the Pareto set more quickly than unanimity rule, 2) majority rule leaves the Pareto set at the same rate as unanimity rule, and 3) majority rule is more likely to select a Pareto optimal outcome than unanimity rule in the final round of play. Our results also suggest that proposers do not behave observationallyrational in the final round and complete information does not affect the primary result.
Stable voting procedures for committees in economic environments
2001
A strong representation of a committee, formalized as a simple game, on a convex and closed set of alternatives is a game form with the members of the committee as players such that (i) the winning coalitions of the simple game are exactly those coalitions, which can get any given alternative independent of the strategies of the complement, and (ii) for any profile of continuous and convex preferences, the resulting game has a strong Nash equilibrium. In the paper, it is investigated whether committees have representations on convex and compact subsets of R m . This is shown to be the case if there are vetoers; for committees with no vetoers the existence of strong representations depends on the structure of the alternative set as well as on that of the committee (its Nakamura-number). Thus, if A is strictly convex, compact, and has smooth boundary, then no committee can have a strong representation on A. On the other hand, if A has non-smooth boundary, representations may exist depending on the Nakamura-number (if it is at least 7). JEL No. D71, C71.
Veto power in committees: an experimental study
Experimental Economics, 2010
In a number of multilateral bargaining situations one or more players has veto powerthe right to unilaterally block decisions but without the ability to unilaterally secure their preferred outcome. Our experimental outcomes show that committees with a veto player take longer to reach decisions (are less efficient) than without a veto player, that veto players proposals generate less consensus then non-veto players proposals, that veto power in conjunction with proposer power generates excessive power for the veto player, and that non-veto players show substantially more willingness to compromise than veto players, with players in the control game somewhere in between. We relate our results to the theoretical literature on the impact of veto power as well as concerns about the impact of veto power in real-life committees.
Committee decisions: Optimality and Equilibrium
2008
We consider a group or committee that faces a binary decision under uncertainty. Each member holds some private information. Members agree which decision should be taken in each state of nature, had this been known, but they may attach different values to the two types of mistake that may occur. Most voting rules have a plethora of uninformative equilibria, and informative voting may be incompatible with equilibrium. We analyze an anonymous randomized majority rule that has a unique equilibrium. This equilibrium is strict, votes are informative, and the equilibrium implements the optimal decision with probability one in the limit as the committee size goes to infinity. We show that this also holds for the usual majority rule under certain perturbations of the behavioral assumptions: (i) a slight preference for voting according to one's conviction, and (ii) transparency and a slight preference for esteem. We also show that a slight probability for voting mistakes strengthens the incentive for informative voting.
Mqite Working paper series WP # 14-05 A Consensual Committee Using Approval Balloting
2014
A new voting rule for electing committees is described. Specifically, we use approval balloting and propose a voting procedure guaranteeing that if a committee representing (in a determined proportion) all voters exists, then the selected committee has to represent all voters at least in the same proportion. This condition is a generalization of the unanimity property and the usual voting procedures in this context do not satisfy it.