The Copeland rule and Condorcet’s principle

Summary. The purpose of this note is to shed some light on the relationship between the Copeland rule and the Condorcet principle in those cases where there does not exist a Condorcet winner. It will be shown that the Copeland rule ranks alternatives according to their distances to being a Condorcet winner.Received: 30 July 2003, Revised: 31 December 2003, JEL Classification Numbers: D70, D71.Christian Klamler: I am very grateful to Daniel Eckert and Nick Baigent for their helpful comments.     

How many voters are needed for paradoxes?

Summary. This paper presents a general procedure for finding profiles with the minimum number of voters required for many important paradoxes. Borda's and Condorcet's classic examples are revisited as well as generalizations. Using Saari's procedure line, we obtain an upper bound for the minimum number of voters needed for a profile for which the Condorcet winner is not strictly top ranked for all weighted positional procedures. Also we give a simple upper bound on the minimum number of voters needed for a set of prescribed voting outcomes. In contrast to situations wherein small numbers of voters are needed, we consider paradoxes requiring arbitrarily large numbers of voters as well as large numbers of alternatives. Finally we indicate connections with statistical rank based tests. Received: April 18, 2001; revised version: May 25, 2001     

The Borda rule,Condorcet consistency and Condorcet stability

Summary. The Borda rule is known to be the least vulnerable scoring rule to Condorcet inconsistency, Saari (2000). Such inconsistency occurs when the Condorcet winner (the alternative which is preferred to any other alternative by a simple majority) is not selected by the Borda rule. This note exposes the relationship between the Borda rule and the Condorcet q-majority principle as well as the Condorcet q-majority voting rule. The main result establishes that the Borda rule is Condorcet q-majority consistent when where k is the number of alternatives. The second result establishes that is the minimal degree of majority decisiveness corresponding to the Borda rule under sincere voting. The same majority is required to ensure decisiveness under the Borda rule and to ensure that a q-rule (the generalized q-majority Condorcet rule) is a voting rule. Received: April 8, 2002; revised version: July 17, 2002 Correspondence to:S. Nitzan     

Electoral Thresholds as Coordination Devices

In this paper, we study one‐person–one‐vote parliamentary elections where voters care both about the winner of elections and about the composition of the parliament. Parties enter the parliament if and only if their vote share exceeds some predetermined threshold. We show that equilibria generically exist in which all parties obtain a non‐degenerate vote‐share and, perhaps more importantly, we show that the size of the electoral threshold acts as a coordination device, which crucially affects the win prospects of the Condorcet winner party. In particular, we argue that the win prospects of the Condorcet winner party decrease with the size of the entry threshold.     

Winning probabilities in a pairwise lottery system with three alternatives

Summary. The pairwise lottery system is a multiple round voting procedure which chooses by lot a winner from a pair of alternatives to advance to the next round where in each round the odds of selection are based on each alternatives majority rule votes. We develop a framework for determining the asymptotic relative likelihood of the lottery selecting in the final round the Borda winner, Condorcet winner, and Condorcet loser for the three alternative case. We also show the procedure is equivalent to a Borda lottery when only a single round of voting is conducted. Finally, we present an alternative voting rule which yields the same winning probabilities as the pairwise lottery in the limiting case as the number of rounds of the pairwise lottery becomes large.Received: 5 June 2003, Revised: 17 June 2004, JEL Classification Numbers: D71. Correspondence to: Jac C. HeckelmanWe thank Keith Dougherty and Andrew Yates for their comments.     

A strategy-proofness characterization of majority rule

Summary. A feasible alternative x is a strong Condorcet winner if for every other feasible alternative y there is some majority coalition that prefers x to y. Let (resp., denote the set of all profiles of linear (resp., merely asymmetric) individual preference relations for which a strong Condorcet winner exists. Majority rule is the only non-dictatorial and strategy-proof social choice rule with domain , and majority rule is the only strategy-proof rule with domain . Received: August 29, 2000; revised version: November 13, 2002 RID="*" ID="*"We are grateful to Wulf Gaertner and our two referees for insightful comments on a previous draft. Correspondence to: D. E. Campbell     

Counterexamples on the Superiority of Approval versus Plurality

We present a simple voting environment with three candidates where the Condorcet winner exists. Under plurality rule, the derived game has a stable set where such a candidate is elected with probability one. However, no stable set of the approval game elects the Condorcet winner with positive probability. We also analyze the robustness of such an example to changes in the number of voters and their preferences. To conclude, we present a generic four‐candidate voting environment with the same properties.     

Decisiveness of contributors’ perceptions in elections

We consider a model of two-candidate elections with a one-dimensional policy space. Spending on campaign advertisements can directly influence voters’ preferences, and contributors give the money for campaign spending in exchange for promised services if the candidate wins. We find that the winner of the election depends crucially on the contributors’ beliefs about who is likely to win and the contribution market tends toward nonsymmetric equilibria in which one of the two candidates has no chance of winning. If the voters are only weakly influenced by advertising or if permissible campaign spending is small, then the candidates choose policies close to the median voter’s ideal point, but the contributors still determine the winner. Uncertainty about the Condorcet winning point (or its nonexistence) can change these results and generate equilibria in which both candidates have substantial probabilities of winning.     

Existence of a Condorcet Winner When Voters Have Other‐Regarding Preferences

In standard political economy models, voters are “self‐interested” that is, care only about “own” utility. However, the emerging evidence indicates that voters often have “other‐regarding preferences” (ORP), that is, in deciding among alternative policies voters care about their payoffs relative to others. We extend a widely used general equilibrium framework in political economy to allow for voters with ORP, as in Fehr and Schmidt (1999) . In line with the evidence, these preferences allow voters to exhibit “envy” and “altruism,” in addition to the standard concern for “own utility.” We give sufficient conditions for the existence of a Condorcet winner when voters have ORP. This could open the way for an incorporation of ORP in a variety of political economy models. Furthermore, as a corollary, we give more general conditions for the existence of a Condorcet winner when voters have purely selfish preferences.     

Politically Determined Income Inequality and the Provision of Public Goods

Political processes may bring about Pareto improvements by increasing income inequality in a society that produces a public good by voluntary contributions. Proportional taxation funds a “governing agent.” The most endowed agent is the Condorcet winner for governing agent. When the tax rate can also be chosen by a vote, the ideal point of the agent with median initial endowment is the Condorcet winner under Cobb–Douglas utility. If Pareto improvements are possible, this ideal point corresponds to Pareto improvement. Pareto improvement may also be possible, even when a Leviathan set taxes, if there is deadweight loss from taxation. Pareto improvements are indeed always possible in “large” societies. On the other hand, no improvements may be possible if the initial distribution of wealth is very unequal in a “small” society, and Condorcet winners may not exist for other utility functions.     

Dominance solvable approval voting games

This work provides necessary and sufficient conditions for the dominance solvability of approval voting games. Our conditions are very simple since they depend just on the number of possible winners when voters play weakly undominated strategies. If there are at most two possible winners, then the game is dominance‐solvable and the outcome coincides with the Condorcet winner. If every candidate is a possible winner, the game is not dominance‐solvable. If none of the previous conditions holds, then the game need not be dominance‐solvable, and the outcome need not coincide with the Condorcet winner.     

Constant scoring rules,condorcet criteria and single-peaked preferences

Summary A constant scoring rule asks each individual to vote for a given (and constant) number of alternatives and the alternative with the most votes is elected. A sequential constant scoring rule applies this principle in a process of sequential elimination. Constant scoring rules as well as sequential constant scoring rules fail to satisfy Condorcet criteria when individual preferences are unrestricted. The purpose of this paper is to show that, if we assume that preferences are single-peaked, then some constant scoring rules satisfy the Condorcet loser criterion and some sequential constant scoring rules satisfy the Condorcet winner criterion. The results we provide make possible the identification of these rules.I thank Maurice Salles and two anonymous referees for their helpful comments. The usual disclaimers apply.     

Approval voting in subset elections

Summary. Approval voting is designed to be “insensitive to numbers” of voters, and likely to elect a Condorcet candidate. However, the result of an election among one group of candidates gives no information about the results of elections among any other groups, even if every voter follows the recommended utility-maximizing strategy, which places strong restrictions on the individual voter's subset ballots. Thus the addition of a single candidate could completely reverse the outcome of an election, or a Condorcet candidate could finish last. Received: November 5, 1998; revised version: November 30, 1998     

POSITIVELY RESPONSIVE COLLECTIVE CHOICE RULES AND MAJORITY RULE: A GENERALIZATION OF MAY'S THEOREM TO MANY ALTERNATIVES

May's theorem shows that if the set of alternatives contains two members, an anonymous and neutral collective choice rule is positively responsive if and only if it is majority rule. We show that if the set of alternatives contains three or more alternatives only the rule that assigns to every problem its strict Condorcet winner satisfies the three conditions plus Nash's version of “independence of irrelevant alternatives” for the domain of problems that have strict Condorcet winners. We show also that no rule satisfies the four conditions for domains that are more than slightly larger.     

Redistributive policies with heterogeneous social preferences of voters

There is growing evidence on the roles of fairness and other-regarding preferences as fundamental human motives. Call voters with fair preferences, as in Fehr and Schmidt (1999), fair-voters. By contrast, traditional political economy models are based on selfish-voters who derive utility solely from “own” payoff. In a general equilibrium model with endogenous labor supply, a mixture of fair and selfish voters choose optimal policy through majority voting. First, we show that majority voting produces a unique winner in pairwise contests over feasible policies (the Condorcet winner). Second, we show that a preference for greater fairness leads to greater redistribution. An increase in the number of fair voters can also lead to greater redistribution. Third, we show that in economies where the majority are selfish-voters, the decisive policy could be chosen by fair-voters, and vice versa. Fourth, while choosing labor supply, even fair voters behave exactly like selfish voters. We show how this apparently inconsistent behavior in different domains (voting and labor supply) can be rationalized within the model.     

Transcendental vs. comparative approaches to justice: a reappraisal of Sen's dichotomy

In The Idea of Justice, Sen describes two competing approaches to theorising about justice: “transcendental institutionalism”, in which he includes Rawls, and “realisation-focused comparison”, in which he includes Condorcet and himself. The objective of this paper is to demonstrate that a comparative approach cannot exist without a transcendental dimension. Contrary to Sen, who claims that a transcendental theory is neither necessary nor sufficient in order to frame comparative judgments, it is shown that a transcendental dimension is a necessary, albeit not sufficient, condition of any comparative approach. To illustrate our thesis, we refer to the works of three great authors: Condorcet, Sen himself and the later Rawls.     

A recursion relation for the probability of the paradox of voting

For alternatives x_i, i = 1,…, m, giving rise to m! linear preference orderings of which one is selected independently by each of N voters, a recursion relation is developed which expresses the probability that x_i is the Condorcet winner when there are N voters in terms of the probability of this event when there are N ? 1 voters. Hence the probabilities of the paradox of voting when N is odd, and of Condorcet indecision when N is even may be obtained. The relationship holds for any set of probabilities, or culture, governing the selection of the preference orderings by the voters.     

How competition affects schools' performances: Does specification matter?

If the number of individuals is odd, majority rule is the only non-dictatorial strategy-proof social choice rule on the domain of linear orders that admit a Condorcet winner (Campbell and Kelly, 2003). This paper shows that the claim is false when the number of individuals is even, and provides a counterpart to the theorem for the even case.     

Approval voting with endogenous candidates

We present a formal model of political competition under approval voting which allows for endogenous candidate entry. Our analysis yields a number of novel insights. First, we develop a notion of sincere voting behavior under approval voting, called relative sincerity. We then show that the relatively sincere voting behavior is consistent with the strategic calculus of voting. Second, we show that in a one-dimensional model with distance preferences, equilibria in relatively sincere strategies and without spoiler candidates always generate outcomes close to the median voter. Moreover, approval voting satisfies Duverger's Law in the sense that there are at most two winning positions! Finally, we extend our analysis to arbitrary policy spaces. In the general setting, approval voting is shown to be susceptible to the same kinds of problems as the plurality rule, such as the possibility of non-majoritarian outcomes, failure to elect the Condorcet winner and existence of spoiler candidates.     

A Solution Concept for Majority Rule in Dynamic Settings

We define and explore the notion of a Dynamic Condorcet Winner (DCW), which extends the notion of a Condorcet winner to dynamic settings. We show that, for every DCW, every member of a large class of dynamic majoritarian games has an equivalent equilibrium, and that other equilibria are not similarly portable across this class of games. Existence of DCWs is guaranteed when members of the community are sufficiently patient. We characterize sustainable and unsustainable outcomes, study the effects of changes in the discount factor, investigate efficiency properties, and explore the potential for achieving renegotiation-proof outcomes. We apply this solution concept to a standard one-dimensional choice problem wherein agents have single-peaked preferences, as well as to one involving the division of a fixed aggregate pay-off.