The evaluation of majority rules in a legislative bargaining model

A budget needs to be distributed among jurisdictions through bargaining in the legislature. Using a simple three-player, three-period Baron and Ferejohn [Baron, D.P., Ferejohn, J.A., 1989. Bargaining in legislatures. American Political Science Review 83 (4), 1181–1206] style legislative bargaining model with incomplete information, we evaluate two kinds of majority rules: the simple majority rule and the unanimity rule. Under the simple majority rule, it is less expensive to form a minimum-winning coalition, so that every type of proposer prefers his proposal to be passed immediately. The proposer has fewer incentives to reveal his information by delaying the bargaining, since there is a possibility of being excluded from the majority in future periods. Thus, in contrast to the unanimity rule, there does not exist any fully separating equilibrium. We also show that if the first-period proposer has greater agenda-setting power, it can help to reduce the probability of delay.     

Committee Design with Endogenous Information

Identical agents gather costly information, and then aggregate it through voting. Because information is a public good, information is underprovided relative to the social optimum. A "good" voting rule must give incentives to acquire information, as well as aggregate information efficiently. A voting rule that requires a large plurality (in the extreme, unanimity) to upset the status quo can be optimal only if the information available to each agent is sufficiently accurate. This result is independent of the preferences of voters and of the cost of information.     

Information in conflicts

We consider two-player contests for a prize of common but uncertain value. For settings where one player knows the value of the prize, while the other only knows its prior distribution, we give conditions for when the uninformed agent is ex ante strictly more likely to win the prize than is the informed agent. In the special case of a lottery contest, equilibrium expenditures are lower under asymmetric information than if either both agents are informed or neither agent is informed.     

Cost sharing with multiple technologies

We study cost sharing problems where gains from cooperation can come from the presence of other agents, such as when agents share their technologies. A simple model is built, where economies of scale are eliminated in order to study this effect. We use as the key axiom the property that, if an agent does not improve the technology of any coalition he joins, he should not get any part of the gain from cooperation. With properties of linearity and symmetry, this axiom characterizes a well-defined set of rules. From this set, we propose a rule derived from the familiar Shapley value. We show that it is the only rule in that set satisfying an upper-limit property on individual cost allocations or a monotonicity property when technology improves. We also derive a distinct rule using a property that ensures that no coalition has an incentive to manipulate the individual demands of its members.     

Cost sharing with multiple technologies

We study cost sharing problems where gains from cooperation can come from the presence of other agents, such as when agents share their technologies. A simple model is built, where economies of scale are eliminated in order to study this effect. We use as the key axiom the property that, if an agent does not improve the technology of any coalition he joins, he should not get any part of the gain from cooperation. With properties of linearity and symmetry, this axiom characterizes a well-defined set of rules. From this set, we propose a rule derived from the familiar Shapley value. We show that it is the only rule in that set satisfying an upper-limit property on individual cost allocations or a monotonicity property when technology improves. We also derive a distinct rule using a property that ensures that no coalition has an incentive to manipulate the individual demands of its members.     

The separability axiom and equal-sharing methods

A quasi-linear social choice problem is defined as selecting one (among finitely many) indivisible public decision and a vector of monetary transfers among agents to cover the cost of this decision. This decision is based upon individual preferences, which are assumed to be additively separable and linear in money. The Separability axiom is a consistency property for choice methods on societies with variable size: the decision is not affected if we remove an arbitrary agent under the condition that he be guaranteed his original utility level and the cost to the remaining agents is modified accordingly. Thus the utility level assigned by the social choice function to agent i is the price at which the other agents are unanimously willing to buy agent is share of the decision power. A general characterization of choice methods satisfying this axiom is provided. Three subclasses of particular interest are characterized by additional milder axioms. Those are: (i) equal sharing of the surplus left over some reference utility (e.g., the utility at a status quo decision), (ii) utilitarian methods that merely select the efficient public decision and perform no monetary transfers, and (iii) equal allocation of nonseparable costs, which divides equally the surplus left over from the utility derived from the pivotal mechanism (also known as the Vickrey-Clarke-Groves mechanism).     

Uniqueness of stationary equilibrium payoffs in coalitional bargaining

We study a model of sequential bargaining in which, in each period before an agreement is reached, the proposer?s identity is randomly determined, the proposer suggests a division of a pie of size one, each other agent either approves or rejects the proposal, and the proposal is implemented if the set of approving agents is a winning coalition for the proposer. The theory of the fixed point index is used to show that stationary equilibrium expected payoffs of this coalitional bargaining game are unique. This generalizes Eraslan [34] insofar as: (a) there are no restrictions on the structure of sets of winning coalitions; (b) different proposers may have different sets of winning coalitions; (c) there may be a positive probability that no proposer is selected.     

A Bayesian Model of Voting in Juries

We model voting in juries as a game of incomplete information, allowing jurors to receive a continuum of signals. We characterize the unique symmetric equilibrium of the game, and give a condition under which no asymmetric equilibria exist under unanimity rule. We offer a condition under which unanimity rule exhibits a bias toward convicting the innocent, regardless of the size of the jury, and give an example showing that this bias can be reversed. We prove a “jury theorem” for our general model: As the size of the jury increases, the probability of a mistaken judgment goes to zero for every voting rule except unanimity rule. For unanimity rule, the probability of making a mistake is bounded strictly above zero if and only if there do not exist arbitrarily strong signals of innocence. Our results explain the asymptotic inefficiency of unanimity rule in finite models and establishes the possibility of asymptotic efficiency, a property that could emerge only in a continuous model. Journal of Economic Literature Classification Numbers: C72, D72.     

Participation incentives in rank order tournaments with endogenous entry

Rank order tournaments, in which the payment to an agent is based upon relative observed performance, are a commonly used compensation scheme. In practice, agents often compete in some (but not all) events in a set of tournaments. The present study considers two mutually exclusive tournaments, in which agents themselves decide which event to enter. An agent bases this decision upon the combination of three distinct effects: a prize effect, a winning probability effect, and an effort cost effect. The precise impact of each of these effects is analyzed. Of particular interest is the possibility that a field of higher quality may be attracted to the event with smaller prizes.      

Selective incentives and intragroup heterogeneity in collective contests

A group taking part in a contest has to confront the collective action problem among its members, and devices of selective incentives are possible means of resolution. We argue that heterogeneous prize‐valuations in a competing group normally prevent effective use of such selective incentives. To substantiate this claim, we adopt cost‐sharing as a means of incentivizing the individual group members. We confirm that homogeneous prize valuations within a group result in a cost‐sharing rule inducing the first‐best individual contributions. As long as the cost‐sharing rule is dependent only on the members’ contributions, however, such a first‐best rule does not exist for a group with intragroup heterogeneity. Our main result clarifies how unequal prize valuations affect the cost‐sharing rule and, in particular, the degree of cost‐sharing. If the relative rate of change of the marginal effort costs is decreasing, it is reduced by intragroup heterogeneity. If the rate is increasing, the cost is fully shared, but it cannot induce the first‐best contributions for the group.     

The Disunity of Unanimity

Unanimity is the optimal voting rule in a world of zero transactions costs, when side payments are impossible. When side payments are available and transactions costs are zero, the voting rule is irrelevant to the ultimate outcome. In the more realistic situation where side payments are allowed but transactions costs are positive, a unanimity voting rule creates situations where the collective choice may fail a proposed measure even if all members favor the measure in principle. This evidences a disunity between unanimity rules and unanimous outcomes. Constitutional design should focus on rules leading to unanimous outcomes, as opposed to unanimity rules.     

Fairness in the Mail and Opportunism in the Internet: A Newspaper Experiment on Ultimatum Bargaining

Abstract. On 11 May 2001, readers of the Berliner Zeitung were invited to participate in an ultimatum bargaining experiment played in the strategy vector mode: each participant chooses not only how much (s)he demands of the DM1,000 pie but also which of the nine possible offers of DM100, 200, …, 900 (s)he would accept or reject. In addition, participants were asked to predict the most frequent type of behavior. Three randomly selected proposer–responder pairs were rewarded according to the rules of ultimatum bargaining and three randomly chosen participants of those who predicted the most frequent type of behavior received a prize of DM500. Decisions could be submitted by mail, fax or via the internet. Behavior is described, statistically analyzed and compared to the usual laboratory ultimatum bargaining results.     

Group strategyproof cost sharing: The role of indifferences

Every agent reports his willingness to pay for one unit of a good. A mechanism allocates goods and cost shares to some agents. We characterize the group strategyproof (GSP) mechanisms under two alternative continuity conditions interpreted as tie-breaking rules. With the maximalist rule (MAX) an indifferent agent is always served. With the minimalist rule (MIN) an indifferent agent does not get a unit of the good.GSP and MAX characterize the cross-monotonic mechanisms. These mechanisms are appropriate whenever symmetry is required. On the other hand, GSP and MIN characterize the sequential mechanisms. These mechanisms are appropriate whenever there is scarcity of the good.Our results are independent of an underlying cost function; they unify and strengthen earlier results for particular classes of cost functions.     

Central governance or subsidiarity: A property-rights approach to federalism

We consider a model where one region in a federation can realize a public project after undertaking value-increasing investments. While negotiations on the federal level ensure that an efficient project size is implemented in equilibrium, non-contractibility of investments causes the overall outcome to differ across regimes. If the region bears the entire implementation costs of its policies, underinvestment prevails and subsidiarity (centralized governance) is superior when spillovers are weak (strong). Conversely, if linear cost sharing arrangements are feasible, decentralized authority often admits a socially optimal outcome while centralized authority (with majority or unanimity rule) does not.     

Waiting to settle: Multilateral bargaining with subjective biases

We study multilateral bargaining games where agents disagree over their bargaining power. We show that if agents are extremely optimistic, there may be costly delays in an arbitrarily long finite game but if optimism is moderate, all sufficiently long games end in immediate agreement. We show that the game with extreme optimism is highly unstable in the finite-horizon, and we examine the ramifications of this instability on the infinite-horizon problem. Finally, we consider other voting rules, and show that the majority-rule may be more efficient than the unanimity rule when agents are optimistic.     

To Majority through the Search for Unanimity

The relative majority rule is characterized, when there are only two alternatives, in terms of axioms of unanimity, reducibility, ontoness (which expresses citizen sovereignty), and no veto power (a weakening of almost unanimity). The strongest axiom is reducibility, which embodies the preference aggregation procedure that successively synthesizes two divergent preferences until divergence disappears and, therefore, unanimity can be applied.     

Search by committee

We consider the problem of sequential search when the decision to stop is made by a committee and show that a unique symmetric stationary equilibrium exists given a log concave distribution of rewards. We compare search by committee to the corresponding single-agent problem and show that committee members are less picky and more conservative than the single agent. We show how (i) increasing committee size holding the plurality fraction constant and (ii) increasing the plurality rule affect the equilibrium acceptance threshold and expected search duration. Finally, we show that unanimity is optimal if committee members are sufficiently patient.     

Bargaining in committees as an extension of Nash's bargaining theory

This paper addresses the following issue: if a set of agents bargain on a set of feasible alternatives ‘in the shadow’ of a voting rule, that is, any agreement can be enforced if a ‘winning coalition’ supports it, what general agreements are likely to arise? In other words: what influence can the voting rule used to settle (possibly nonunanimous) agreements have on the outcome of consensus? We model the situation as an extension of the Nash bargaining problem in which an arbitrary voting rule replaces unanimity. In this setting a natural extension of Nash's solution is characterized.     

Mechanism Design under Alternative Information Structures and Constrained Capacity

In applied models, the choice of a particular incomplete information structure appears to have been motivated primarily by technical convenience. The information structures used can be classified as either probabilistic or partitional. Information is probabilistic if no agent can rule out any type profile of the remaining agents and, for at least one type of one agent, the conditional and marginal probability distributions over the remaining agents' types are not equal. Information is partitional if the only information the agents have is that one or more agents (individually) can rule out type profiles of the remaining agents and, for at least one type of one agent, that agent has information about the remaining agents. Partitional information includes complete information as a special case. Existing results on complete information environments suggest that partitional information might simplify implementation problems. Within the context of an applied agency model in which capacity is constrained, we provide results that seem to challenge this intuition.Journal of Economic LiteratureClassification Numbers: C72, D82.     

Non-cooperative bargaining and the incomplete informational core

In an exchange economy with incomplete information, the signaling core is defined by the set of state-contingent allocations to which no coalitions object under informational leakage through proposals by informed agents. An objection underlying the signaling core is supported by a sequential equilibrium of an ultimatum bargaining game with an informed proposer. We prove that a stationary sequential equilibrium allocation in a Rubinstein-type sequential bargaining game with a restart rule belongs to the signaling core if the belief of players satisfies a self-selection property.