We propose the concept of level r consensus as a useful property of a preference profile which considerably enhances the stability of social choice. This concept involves a weakening of unanimity, the most extreme form of consensus. It is shown that if a preference profile exhibits level r...

We investigate how individuals think groups should aggregate members' ordinal preferences - that is, how they interpret "the will of the people." In an experiment, we elicit revealed attitudes toward ordinal preference aggregation and classify subjects according to the rules they apparently...

In this note, we use the technique of option sets to sort out the implications of coalitional strategyproofness in the spatial setting. We also discuss related issues and open problems.

All social choice functions are manipulable when more than two alternatives are available. I evaluate the manipulability of the Borda count, plurality rule, minimax set, and uncovered set. Four measures of manipulability are defined and computed stochastically for small numbers of agents and...

Many aspects of social welfare are intrinsically multidimensional. Composite indices at-tempting to reduce this complexity to a unique measure abound in many areas of economics and public policy. Comparisons based on such measures depend, sometimes critically, on how the different dimensions of...

When a group of voters selects a committee out of a set of candidates, it is common and often desirable to endow these voters with some veto power. I present impossibility results showing that even limited veto power makes many mechanisms of interest manipulable. This applies in particular (i)...

This paper studies coalitional strategy-proofness of social choice correspondences that map preference profiles into sets of alternatives. In particular, we focus on the Pareto rule, which associates the set of Pareto optimal alternatives with each preference profile, and examine whether or not...

This paper analyzes strategy-proof collective choice rules when individuals have single-crossing preferences on a finite and ordered set of social alternatives. It shows that a social choice rule is anonymous, unanimous, and strategy-proof on a maximal single-crossing domain if and only if it is...

We analyze a discrete-time search problem in which committee members inspect alternatives sequentially over a finite search horizon. A collective decision to stop searching and accept the current alternative is reached when it is supported by a threshold number of individual votes. We...

This paper introduces excluding outlier voters (EOV) as a general mechanism for revealing true preferences in social choices, and for discouraging voters from strategic voting and manipula-tion. This mechanism is general in that it can be implemented with any voting system. The paper...