Social Choice and Welfare最新文献

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.

The classic cake cutting problem concerns the fair allocation of a heterogeneous resource among interested agents. In this paper, we study a public goods variant of the problem, where instead of competing with one another for the cake, the agents all share the same subset of the cake which must be chosen subject to a length constraint. We focus on the design of truthful and fair mechanisms in the presence of strategic agents who have piecewise uniform (i.e., approval) utilities over the cake. On the one hand, we show that the leximin solution is excludably truthful (meaning it is truthful when it can block each agent from accessing parts of the cake that the agent does not claim to desire) and moreover maximizes the guaranteed normalized egalitarian welfare among all excludably truthful and position oblivious mechanisms. On the other hand, we demonstrate that the maximum Nash welfare solution is excludably truthful for two agents (as it coincides with leximin in that case) but not in general. We also provide an impossibility result on truthfulness when blocking is not allowed, and adapt notions of representation to our setting.

We study a setting in which a community wishes to identify a strongly supported proposal from a space of alternatives, in order to change the status quo. We describe a deliberation process in which agents dynamically form coalitions around proposals that they prefer over the status quo. We formulate conditions on the space of proposals and on the ways in which coalitions are formed that guarantee deliberation to succeed, that is, to terminate by identifying a proposal with the largest possible support. Our results provide theoretical foundations for the analysis of deliberative processes such as the ones that take place in online systems for democratic deliberation support.

John Broome (Proc Aristot Soc 91:87–101, 1990) has developed an influential theory of fairness, which has generated a thriving debate about the nature of fairness. In its initial conception, Broomean fairness is limited to a comparative notion. More recent commentators such as Hooker (Ethical Theory Moral Pract 8:329–52, 2005), Saunders (Res Publica 16:41–55, 2010), Lazenby (Utilitas 26:331–345, 2014), Curtis (Analysis 74:47–57, 2014) have advocated, for different reasons, to also take into account non-comparative fairness. Curtis’ (Analysis 74:47-57, 2014) theory does just that. He also claims that he furthers Broome’s theory by saying precisely what one must do in order to be fair. However, Curtis departs from Broome’s (Proc Aristot Soc 91:87-101, 1990) requirement that claims are satisfied in proportion to their strength. He neglects claim-strengths altogether and identifies claims with their amount. As a result, the theory of Curtis has limited scope. I present a theory of fairness that fulfils all three desiderata: it incorporates non-comparative fairness, it recognizes that claims have both amounts and strengths, and it tells us precisely what one must do in order to be fair.

We study the matching of workers to firms in which workers choose an observable and contractable effort after the match. If there are complementarities between a worker’s ability and a firm’s technology, positive assortative matching (PAM) is the only matching in any equilibrium and is the unique efficient matching. We investigate the effect of a policy that changes the matching of firms to workers from any matching to PAM, such as implementing a centralized clearing house. We characterize two sets of sufficient conditions on the production and cost functions under which the total output and welfare both increase. Under the first set of conditions, the increase in total output is an upper bound for the efficiency gain. In contrast, under the second set of conditions, the increase in total output is a lower bound for the efficiency gain. We identify a third set of conditions under which the total output decreases while welfare increases.

In this paper we propose a simple axiom which, along with the axioms of additivity (transfer) and dummy player, characterizes the Shapley value (the Shapley–Shubik power index) on the domain of TU (simple) games. The new axiom, cross invariance, demands payoff invariance on symmetric players across “quasi-symmetric games,” that is, games where excluding null players, all players are symmetric. Additionally, we demonstrate that the axiom of additivity can be replaced by a new axiom called strong monotonicity, or it can be completely dropped if a stronger version of cross invariance is employed. We also show that the weighted Shapley values can be characterized using a weighted variant of cross invariance. Efficiency is derived rather than assumed in our characterizations. This fresh perspective contributes to a deeper understanding of the Shapley value and its applicability.