Strategy-proofness of the randomized Condorcet voting system
Name
355_2017_1031_ReferencePDF.pdf
Size
341.72 KB
Format
Adobe PDF
Checksum (MD5)
2acc46280524c144b9ba987a795b3110
Author(s)
Hoang, Le Nguyen
Date Issued
February 2017
Journal
Social Choice and Welfare
Publisher
Springer Berlin Heidelberg
Citation
Hoang, Lê Nguyên. “Strategy-Proofness of the Randomized Condorcet Voting System.” Social Choice and Welfare 48, no. 3 (February 13, 2017): 679–701.
Version
Author's final manuscript
Abstract
In this paper, we study the strategy-proofness properties of the randomized Condorcet voting system (RCVS). Discovered at several occasions independently, the RCVS is arguably the natural extension of the Condorcet method to cases where a deterministic Condorcet winner does not exists. Indeed, it selects the always-existing and essentially unique Condorcet winner of lotteries over alternatives. Our main result is that, in a certain class of voting systems based on pairwise comparisons of alternatives, the RCVS is the only one to be Condorcet-proof. By Condorcet-proof, we mean that, when a Condorcet winner exists, it must be selected and no voter has incentives to misreport his preferences. We also prove two theorems about group-strategy-proofness. On one hand, we prove that there is no group-strategy-proof voting system that always selects existing Condorcet winners. On the other hand, we prove that, when preferences have a one-dimensional structure, the RCVS is group-strategy-proof.
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Laboratory for Information and Decision Systems
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1007/s00355-017-1031-2
