Social Choice and Welfare最新文献

Abstract

This paper studies a general class of social choice problems in which agents’ payoff functions (or types) are privately observable random variables, and monetary transfers are not available. We consider cardinal social choice functions which may respond to agents’ preference intensities as well as preference rankings. We show that a social choice function is ex ante Pareto efficient and Bayesian incentive compatible if and only if it is dictatorial. The result holds for arbitrary numbers of agents and alternatives, and under a fairly weak assumption on the joint distribution of types, which allows for arbitrary correlations and asymmetries.

Power measures are used to quantify the influence of members of a democratic institution. We consider voting games with abstention or (3,2) games, which are decision-making processes in which voting options include yes, no and abstention. The power indices that we study are based on the notions of minimal and shift minimal winning tripartitions. We define and characterize the Deegan–Packel and shift Deegan–Packel power indices in the class of (3,2) games. Furthermore, owing to the parameterization result obtained by Freixas et al. (Discret Appl Math 255:21–39, 2019), we provide computational formulae of these indices in the class of I-complete (3,2) games. These formulae allow us to determine the power of each player in a game, regardless of the number of minimal and/or shift minimal winning tripartitions of the game.

We study the problem of allocating packages of different objects to a group of bidders. A rule is overbidding-proof if no bidder has incentives to bid above his actual valuations. We prove that if an efficient rule is overbidding-proof, then each winning bidder pays a price between his winning bid and what he would pay in a Vickrey auction for the same package. In counterpart, the set of rules that satisfy underbidding-proofness always charge a price below the corresponding Vickrey price. A new characterization of the Vickrey allocation rule is provided with a weak form of strategy-proofness. The Vickrey rule is the only rule that satisfies efficiency, individual rationality, overbidding-proofness and underbidding-proofness. Our results are also valid on the domains of monotonic valuations and of single-minded bidders. Finally a family of overbidding rules is introduced that price the assigned packages at a fixed average of the Vickrey price and the pay-as-bid price.

Abstract

In this paper, we challenge the claim that a conservative central bank strengthens the likelihood of a conservative government. In contrast, if an election is based on the comparative advantages of the candidates, an inflation-averse central banker can deter the chances of a conservative candidate because once inflation is removed, its comparative advantage in the fight against inflation disappears. We develop a theory based on a policy-mix game with electoral competition, predicting that a tighter monetary policy reduces the chances of a conservative (i.e., inflation-adverse) party while enhancing the chances for a liberal party. To test these predictions, we examine monthly data of British political history between 1987 and 2015, and show that an increase in the interest rate in the 10 months preceding a national election decreases the popularity of a Tory government. Our analysis on a panel of six OECD countries reveals that a pre-election increase of 1 percentage point in the main targeted interest rate rises the popularity of liberal parties by around 3.43 percentage points relative to its trend.

In the classical bargaining problem, we propose a very mild axiom of individual rationality, which we call possibility of utility gain. This requires that for at least one bargaining problem, there exists at least one player who reaches a higher utility level than their disagreement utility. This paper shows that the Nash solution (Nash in Econometrica 18(2):155–162, 1950) is characterized by possibility of utility gain and continuity with respect to feasible sets together with Nash’s axioms except weak Pareto optimality. We also show that in Nash’s theorem, weak Pareto optimality can be replaced by conflict-freeness (introduced by Rachmilevitch in Math Soc Sci 76(C):107–109, 2015). This demands that when the agreement most preferred by all players is feasible, this should be chosen. Furthermore, we provide alternative and unified proofs for other efficiency-free characterizations of the Nash solution. This clarifies the role of each axiom in the related results.

Abstract

We consider a voting scenario in which the resource to be voted upon may consist of both indivisible and divisible goods. This setting generalizes both the well-studied model of multiwinner voting and the recently introduced model of cake sharing. Under approval votes, we propose two variants of the extended justified representation (EJR) notion from multiwinner voting, a stronger one called EJR for mixed goods (EJR-M) and a weaker one called EJR up to 1 (EJR-1). We extend three multiwinner voting rules to our setting—GreedyEJR, the method of equal shares (MES), and proportional approval voting (PAV)—and show that while all three generalizations satisfy EJR-1, only the first one provides EJR-M. In addition, we derive tight bounds on the proportionality degree implied by EJR-M and EJR-1, and investigate the proportionality degree of our proposed rules.

Quadratic funding is a public good provision mechanism that satisfies desirable theoretical properties, such as efficiency under complete information, and has been gaining popularity in practical applications. We evaluate this mechanism in a setting of incomplete information regarding individual preferences, and show that this result only holds under knife-edge conditions. We also estimate the inefficiency of the mechanism in a variety of settings, and characterize circumstances in which inefficiency increases with population size. We show how these findings can be used to estimate the mechanism’s inefficiency in a wide range of situations under incomplete information.

We characterize a new class of individual measures of economic insecurity in a setting where there is a single relevant variable that can be interpreted as income or consumption. Insecurity is intended to capture the difficulties faced by an economic agent when confronted with adverse events. We work with an intertemporal model and base our measures on the changes in the variable when moving from one period to the next. Our approach is axiomatic and differs from the existing literature in two respects. First, we adopt a relative (scale-invariant) concept of insecurity and, second, we restrict attention to a relatively small set of requirements that we consider plausible and intuitively appealing. As a result, we identify a large class of measures that can be thought of as providing a tool box to empirical researchers who can select those members of our class that they consider suitable for the application in question. In addition, we present a dominance criterion based on our new insecurity measures.

The performance of coalitions is an important measure for evaluating individuals. Sport players, researchers, and firm workers are often judged with their team performances. The social ranking solution (SRS) is a function that maps the ranking on the set of all feasible coalitions (the domain of coalitions) into the ranking of individuals. Importing the axiom of consistency from voting theory, we study consistent SRSs under the variable domains of coalitions. We suppose that there are several domains of coalitions (e.g., a set of research teams made up of only young researchers and a set of research teams including senior researchers), and the individuals are required to be evaluated consistently on each domain of coalition. Such a situation is typical because all the logically possible coalitions are often too huge to deal with. We obtain a new characterization of the lexicographic excellence solution (LES) and its dual (DLES): they are the only SRSs satisfying consistency, neutrality, weak coalitional anonymity, and complete dominance. This characterization is expected to provide a new ground for determining the impacts of individuals based on the lexicographic comparisons of their team performances.

Imagine that the judgments of some individuals on some issues are aggregated into collective judgments. Social deliberation about the issues prior to aggregation can lead to improved judgments, at both the individual and the collective level. In this paper I argue that the epistemic justification for a social deliberation design depends on the chosen judgment aggregation rule, and vice versa. This claim consists of two parts. First, the epistemic superiority of one deliberation design over another or over the absence of any deliberation depends on which procedure is subsequently used to aggregate individual judgments. Second, the epistemic superiority of one aggregation procedure over another depends on how the preceding social deliberation was designed. In short, the choice of deliberation design and of aggregation rule are intertwined. This claim is substantiated by two models. Both models display a tragic rise in competence: social deliberation raises individual competence while reducing collective competence. Here, individual and social epistemology come interestingly apart.