STRATEGIC CANDIDACY AND SINGLE‐PEAKEDNESS*

In elections, the voting outcomes are affected by strategic entries of candidates. We study a class of voting rules immune to strategic candidacy. Dutta et al. (2001 ) show that such rules satisfying unanimity are dictatorial if all orderings of candidates are admissible for voters’ preferences. When voters’ preferences are single‐peaked over a political spectrum, there exist non‐dictatorial rules immune to strategic candidacy. An example is the rule selecting the m‐th peak from the left among the peaks of voters’ preferences, where m is any natural number no more than the number of voters. We show that immunity from strategic candidacy with basic axioms fully characterizes the family of the m‐th leftmost peak rules.     

On the informational efficiency of simple scoring rules

We study information aggregation in large elections. With two candidates, efficient information aggregation is possible (e.g., Feddersen and Pesendorfer [5], [6] and [7]). We show that this result does not extend to elections with more than two candidates. We study a class of simple scoring rules in voting games with Poisson population uncertainty and three candidates. No simple scoring rule aggregates information efficiently, even if preferences are dichotomous and a Condorcet winner always exists. We introduce a weaker criterion of informational efficiency that requires a voting rule to have at least one efficient equilibrium. Only approval voting satisfies this criterion.     

Proposal power and majority rule in multilateral bargaining with costly recognition

This paper studies a sequential bargaining model in which agents expend efforts to be the proposer. In equilibrium, agents’ effort choices are influenced by the prize and cost effects. The (endogenous) prize is the difference between the residual surplus an agent obtains when he is the proposer and the payment he expects to receive when he is not. Main results include: (1) under the unanimity voting rule, two agents with equal marginal costs propose with equal probabilities, regardless of their time preferences; (2) under a nonunanimity rule, however, the more patient agent proposes with a greater probability; (3) while, under the unanimity rule, the social cost decreases in group heterogeneity, it can increase under a nonunanimity rule; and (4) when agents are identical, the unanimity rule is socially optimal.     

Bribe-proof rules in the division problem

The division problem consists of allocating an amount of a perfectly divisible good among a group of n agents with single-peaked preferences. A rule maps preference profiles into n shares of the amount to be allocated. A rule is bribe-proof if no group of agents can compensate one of its subgroups to misrepresent their preferences and, after an appropriate redistribution of their shares, each obtains a weakly preferred share and all agents in the misrepresenting subgroup obtain a strictly preferred share. We characterize all bribe-proof rules as the class of Pareto efficient, strategy-proof, and weakly replacement monotonic rules. This class is larger than the set of sequential allotment rules identified in Barberà et al. [Barberà, S., Jackson, M., Neme, A., 1997. Strategy-proof allotment rules. Games Econ. Behav. 18, 1–21].     

Bribe-proof rules in the division problem

The division problem consists of allocating an amount of a perfectly divisible good among a group of n agents with single-peaked preferences. A rule maps preference profiles into n shares of the amount to be allocated. A rule is bribe-proof if no group of agents can compensate one of its subgroups to misrepresent their preferences and, after an appropriate redistribution of their shares, each obtains a weakly preferred share and all agents in the misrepresenting subgroup obtain a strictly preferred share. We characterize all bribe-proof rules as the class of Pareto efficient, strategy-proof, and weakly replacement monotonic rules. This class is larger than the set of sequential allotment rules identified in Barberà et al. [Barberà, S., Jackson, M., Neme, A., 1997. Strategy-proof allotment rules. Games Econ. Behav. 18, 1–21].     

PUBLIC GOOD PROVISION WITH CONSTITUTIONAL CONSTRAINT

This article studies the public good provision problem, in which the principal faces a constitutional constraint in the sense that in order for a public good provision mechanism to be implemented, it must first be approved by agents under a prespecified voting rule. I find that as long as the voting rule is not the unanimity rule, the principal can propose a mechanism such that first‐best efficiency of provision of the public good is achieved. I also consider various constraints, such as prohibition of discriminatory mechanisms and the existence of vote buying, and discuss optimal voting rules in these situations.     

The (sub-)optimality of the majority rule

We consider collective choice from two alternatives. Ex-ante, each agent is uncertain about which alternative she prefers, and may be uncertain about the intensity of her preferences. An environment is given by a probability distribution over utility vectors that is symmetric across agents and neutral across alternatives. In many environments, the majority voting rule maximizes agents? ex-ante expected utilities among all anonymous and dominant-strategy implementable choice rules. But in some environments where the agents? utilities are stochastically correlated, other dominant-strategy choice rules are better for all agents. If utilities are stochastically independent across agents, majority voting is ex-ante optimal among all anonymous and incentive-compatible rules. We also compare rules from an interim-viewpoint.     

Individually rational rules for the division problem when the number of units to be allotted is endogenous

We study individually rational rules to be used to allot, among a group of agents, a perfectly divisible good that is freely available only in whole units. A rule is individually rational if, at each preference profile, each agent finds that her allotment is at least as good as any whole unit of the good. We study and characterize two individually rational and efficient families of rules, whenever agents' preferences are symmetric single-peaked on the set of possible allotments. Rules in the two families are in addition envy-free, but they differ on whether envy-freeness is considered on losses or on awards. Our main result states that (a) the family of constrained equal losses rules coincides with the class of all individually rational and efficient rules that satisfy justified envy-freeness on losses and (b) the family of constrained equal awards rules coincides with the class of all individually rational and efficient rules that satisfy envy-freeness on awards.     

A Coalition-Form Analysis Of The “One Country - One Vote” Rule In The Governing Council Of The European Central Bank *

This paper analyses the “one country—one vote” rule for monetary policy decision

making of the Governing Council of the European Central Bank in a framework of cooperative game theory. The Shapley value is used as a solution concept. In contrast to former papers analysing the allocation of abstract "voting power" in committees of international organisations, preferences for monetary policy are modelled to obtain a prediction about potential transfers implied by an equal allocation of voting rights when countries are of different size. It is shown that if the number of countries participating to a currency union grows and the weight of the largest country within the currency union becomes small, the allocation of voting rights becomes irrelevant in the sense that transfers per country tend in any case to zero. [C71, E5, F02]     

Fully sincere voting

In a general social choice framework where the requirement of strategy-proofness may not be sensible, we call a social choice rule fully sincere if it never gives any individual an incentive to vote for a less-preferred alternative over a more-preferred one and provides an incentive to vote for an alternative if and only if it is preferred to the default option that would result from abstaining. If the social choice rule can depend only on the number of votes that each alternative receives, those rules satisfying full sincerity are convex combinations of the rule that chooses each alternative with probability equal to the proportion of the vote it receives and an arbitrary rule that ignores voters' preferences. We note a sense in which the natural probabilistic analog of approval voting is the fully sincere rule that allows voters maximal flexibility in expressing their preferences and gives these preferences maximal weight.     

Fully sincere voting

In a general social choice framework where the requirement of strategy-proofness may not be sensible, we call a social choice rule fully sincere if it never gives any individual an incentive to vote for a less-preferred alternative over a more-preferred one and provides an incentive to vote for an alternative if and only if it is preferred to the default option that would result from abstaining. If the social choice rule can depend only on the number of votes that each alternative receives, those rules satisfying full sincerity are convex combinations of the rule that chooses each alternative with probability equal to the proportion of the vote it receives and an arbitrary rule that ignores voters' preferences. We note a sense in which the natural probabilistic analog of approval voting is the fully sincere rule that allows voters maximal flexibility in expressing their preferences and gives these preferences maximal weight.     

The Costs of Implementing the Majority Principle: The Golden Voting Rule

In a context of constitutional choice of a voting rule, this paper presents an economic analysis of scoring rules that identifies the golden voting rule under the impartial culture assumption. This golden rule depends on the weights β and (1−β) assigned to two types of costs: the cost of majority decisiveness (‘tyranny’) and the cost of the ‘erosion’ in the majority principle. Our first main result establishes that in voting contexts where the number of voters n is typically considerably larger than the number of candidates k, the golden voting rule is the inverse plurality rule for almost any positive β. Irrespective of n and k, the golden voting rule is the inverse plurality rule if β ≥ 1/2 .. This hitherto almost unnoticed rule outperforms any other scoring rule in eliminating majority decisiveness. The golden voting rule is, however, the plurality rule, the most widely used voting rule that does not allow even the slightest ‘erosion’ in the majority principle, when β=0. Our second main result establishes that for sufficiently “small size” voting bodies, the set of potential golden rules consists at most of just three rules: the plurality rule, the Borda rule and the inverse plurality rule. On the one hand, this finding provides a new rationalization to the central role the former two rules play in practice and in the voting theory literature. On the other hand, it provides further support to the inverse plurality rule; not only that it is the golden rule in voting contexts, it also belongs, together with the plurality rule and the Borda method of counts, to the “exclusive” set of potential golden voting rules in small committees. We are indebted to Jim Buchanan, Amichai Glazer, Noa Nitzan, Ken Shepsle, and an anonymous referee for their useful comments.     

Testing Social Preferences for an Economic “Bad”: An Artefactual Field Experiment*

We test for social preferences over a commodity in an artefactual field experiment using the random price voting mechanism. Subjects are university staff members, and the commodity is water “contaminated” by a sterilized cockroach. Our results suggest that social preferences exist with respect to commodities and “bads”, supporting a more general utility framework for social preferences. Our empirical test allows for the coexistence of three social‐preference models; our results support the models of Fehr and Schmidt (1999) and Charness and Rabin (2002), but not the model of Bolton and Ockenfels (2000). Also, we find that incorporating social preferences improves the efficiency of majority‐rules voting.     

Voting for Burden Sharing Rules in Public Goods Games

We experimentally investigate whether groups of heterogeneous agents can reach an agreement on how to share the costs of providing a public good. Thereby, we explore the performance of different burden sharing rules being implemented either endogenously or exogenously. In case of an endogenously implemented burden sharing rule, subjects vote for different burden sharing schemes either by unanimity or majority vote. Despite the fact that preferences for the allocation schemes differ among agents, most groups agree upon a common scheme, and consequently avoid an uncoordinated action. Our results reveal both the opportunities and risks of burden sharing negotiations. We find average efficiency levels to increase in case an agreement is reached. If groups however fail to agree upon a common rule, cooperation collapses and efficiency levels decrease compared to a voluntary contribution mechanism being exogenously imposed. Most importantly, agents who face a voting decision on average receive higher payoffs than agents in an exogenously implemented voluntary contribution mechanism and do not earn less than participants in any externally determined burden sharing rule.     

Solidarity and Probabilistic Target Rules

We consider a probabilistic approach to collective choice problems where a group of agents with single-peaked preferences have to decide on the level or location of a public good. We show that every probabilistic rule that satisfies Pareto efficiency and "solidarity" (population-monotonicity or replacement-domination) must equal a so-called target rule.     

General allocation problems with single-peaked preferences: path-independence and related topics

We face the problem of allocationg a fixed amount of a perfectly divisible good among a group of agents with single-peaked preferences. We survey the three different cases studied in the literature: the pure distribution case, the redistribution case, and the gerneral case. The so called general case provide with a natural framework to analyze the idea of path-independence. In this framework, we explore the existence of rules fulfilling this property. Our first result is negative: a strong version of this property cannot be fulfilled together with efficiency. Nonetheless, some restricted versions of the path-independence property are compatible with interesting properties, in particular no manipulability, and no envy. We then identify two solutions satisfying this sort of property: the equal distance rule, and a new extension of the uniform rule.     

Strategy-Proofness and the Tops-Only Property

A social choice function satisfies the tops‐only property if the chosen alternative only depends on each person's report of his most‐preferred alternatives on the range of this function. On many domains, strategy‐proofness implies the tops‐only property provided that the range of the social choice function satisfies some regularity condition. The existing proofs of this result are model specific. In this paper, a general proof strategy is proposed for showing that a strategy‐proof social choice function satisfies the tops‐only property when everyone has the same set of admissible preferences.     

Voting with abstention

Most voting models in the literature neglect abstention, but is such a simplification justified? I investigate this question in a model with outside pressure on voters. For sequential voting (e.g., roll call votes), with and without an abstention option, there is a unique subgame perfect equilibrium, which implies that true majorities always succeed. Abstention can be an equilibrium strategy for some voters, in particular under complex decision rules (e.g., weighted voting, double majorities). Simultaneous voting often has a unique pure strategy equilibrium but also a plethora of mixed and pure/mixed strategy equilibria. Therefore, only with equilibrium selection, can we evaluate the consequences of neglecting abstention. For equal weight voting, equilibria selected by the procedure of Harsanyi and Selten change completely with an abstention option, even if abstention itself is not or rarely used. With small enough outside pressure, however, the selected equilibrium honors true majorities in both cases.     

Voting on public goods in multi-jurisdictional systems

This paper studies an economy with multiple jurisdictions, each producing a (pure) public good. Decisions are taken by means of a centralized voting procedure, to which individual agents participate and whose rules are defined with respect to the jurisdictional structure. In particular, a winning alternative must gain the support of a given number of jurisdictions. A well-known example is qualified majority rules. We establish condition on voting rules for the set of voting equilibria to coincide with the set of ratio equilibria of the economy, under alternative assumptions on the possibility of transfers across jurisdictions. We employ the obtained results to characterize the equilibria of two-stage voting situations, in which jurisdictional delegates vote instructed by internal committees.     

Convergence Results for Unanimous Voting

This paper derives a necessary condition for unanimous voting to converge to the perfect information outcome when voters are only imperfectly informed about the alternatives. Under some continuity assumptions, the condition is also sufficient for the existence of a sequence of equilibria that exhibits convergence. The requirement is equivalent to that found by Milgrom [1979, Econometrica47, 679-688] for information aggregation in single-prize auctions. An example illustrates that convergence may be reasonably fast for small committees. However, if voters have common preferences, unanimity is not the optimal voting rule. Unanimity rule makes sense only as a way to ensure minority views are respected. Journal of Economic Literature Classification Numbers: D72, D82, D44.