Condorcet winners on median spaces

We characterize the outcome of majority voting for single--peaked preferences on median spaces. This large class of preferences covers a variety of multi--dimensional policy spaces including products of lines (e.g.\ grids), trees, and hypercubes. Our main result is the following: If a Condorcet winner (i.e.\ a winner in pairwise majority voting) exists, then it coincides with the appropriately defined median (``the median voter''). This result generalizes previous findings which are either restricted to a one--dimensional policy space or to the assumption that any two voters with the same preference peak must have identical preferences. The result applies to models of spatial competition between two political candidates. A bridge to the graph--theoretic literature is built

Condorcet winners on median spaces

We characterize the outcome of majority voting for single-peaked preferences on median spaces. This large class of preferences covers a variety of multi-dimensional policy spaces including products of lines (e.g. grids), trees, and hypercubes. Our main result is the following: If a Condorcet winner (i.e. a winner in pairwise majority voting) exists, then it coincides with the appropriately defined median ("the median voter"). This result generalizes previous findings which are either restricted to a one- dimensional policy space or to the assumption that any two voters with the same preference peak must have identical preferences. The result applies to models of spatial competition between two political candidates. A bridge to the graph-theoretic literature is built

Condorcet winners on median spaces

We characterize the outcome of majority voting for single--peaked preferences on median spaces. This large class of preferences covers a variety of multi--dimensional policy spaces including products of lines (e.g.\ grids), trees, and hypercubes. Our main result is the following: If a Condorcet winner (i.e.\ a winner in pairwise majority voting) exists, then it coincides with the appropriately defined median (``the median voter''). This result generalizes previous findings which are either restricted to a one--dimensional policy space or to the assumption that any two voters with the same preference peak must have identical preferences. The result applies to models of spatial competition between two political candidates. A bridge to the graph--theoretic literature is built

Laboratory Experiments in Political Economy

Most of the laboratory research in political science follows the style that was pioneered in experimental economics a half-century ago by Vernon Smith. The connection between this style of political science experimentation and economics experimentation parallels the connection between economic theory and formal political theory.

Redistribution in the Open Economy: A Political Economy Approach

This paper develops a two-country model of international trade in which citizens who are heterogeneous with respect to their factor endowments vote over tariffs and income tax rates. In the politico-economic equilibrium, each country chooses its national policies by majority voting, taking the policy choice of the other country as given. By incorporating both income and trade taxes in a unified international-trade framework, we uncover the interplay between majority voting over these two instruments at the domestic level and strategic interdependencies between countries’ trade policies. Our main result is that greater inequality can be conducive to more redistribution via income taxation, more protectionist policies in capital-abundant countries, and less protectionist policies in labour-abundant countries. The model can accommodate the predictions of recent empirical studies on the relationship between inequality, protectionism, and redistribution.International trade, majority voting, inequality, income taxation, tariffs.

Condorcet solutions in frugal models of budget allocation

We study a voting model with incomplete information in which the evaluation of social welfare must be based on information about agents’ top choices plus general qualitative background conditions on preferences. The former is elicited individually, while the latter is not. We apply this ‘frugal aggregation’ model to multi-dimensional budget allocation problems, relying on the specific assumptions of convexity and separability of preferences. We propose a solution concept of ex-ante Condorcet winners which is widely and flexibly applicable and naturally incorporates the epistemic assumptions of particular frugal aggregation models. We show that for the case of convex preferences, the ex-ante Condorcet approach naturally leads to a refinement of the Tukey median. By contrast, in the case of separably convex preferences, the same approach leads to different solution, the 1-median, i.e. the minimization of the sum of the L1-distances to the agents’ tops. An algorithmic characterization renders the latter solution analytically tractable and efficiently computable

A Decade of Experimental Research on Spatial Models of Elections and Committees

The Euclidean representation of political issues and alternative outcomes, and the associated representation of preferences as quasi-concave utility functions is by now a staple of formal models of committees and elections. This theoretical development, moreover, is accompanied by a considerable body of experimental research. We can view that research in two ways: as a test of the basic propositions about equilibria in specific institutional settings, and as an attempt to gain insights into those aspects of political processes that are poorly understood or imperfectly modeled, such as the robustness of theoretical results with respect to procedural details and bargaining environments. This essay reviews that research so that we can gain some sense of its overall import

Consensus theories: an oriented survey

This article surveys seven directions of consensus theories: Arrowian results, federation consensus rules, metric consensus rules, tournament solutions, restricted domains, abstract consensus theories, algorithmic and complexity issues. This survey is oriented in the sense that it is mainly – but not exclusively – concentrated on the most significant results obtained, sometimes with other searchers, by a team of French searchers who are or were full or associate members of the Centre d'Analyse et de Mathématique Sociale (CAMS).Consensus theories ; Arrowian results ; aggregation rules ; metric consensus rules ; median ; tournament solutions ; restricted domains ; lower valuations ; median semilattice ; complexity

Combining Voting Rules Together

We propose a simple method for combining together voting rules that performs a run-off between the different winners of each voting rule. We prove that this combinator has several good properties. For instance, even if just one of the base voting rules has a desirable property like Condorcet consistency, the combination inherits this property. In addition, we prove that combining voting rules together in this way can make finding a manipulation more computationally difficult. Finally, we study the impact of this combinator on approximation methods that find close to optimal manipulations