Nash Equilibria for Quadratic Voting

56 Pages Posted: 30 Aug 2014 Last revised: 18 Jul 2019

See all articles by Steven Lalley

Steven Lalley

Department of Statistics, University of Chicago

E. Glen Weyl

Microsoft Research New York City; RadicalxChange Foundation

Date Written: July 16, 2019

Abstract

A group of N individuals must choose between two collective alternatives. Under Quadratic Voting (QV), agents buy votes in favor of their preferred alternative from a clearing house, paying the square of the number of votes purchased; the sum of all votes purchased determines the outcome. We provide the first rigorous results for this mechanism, in a canonical independent private values environment with bounded value distributions. In addition to characterizing the nature of equilibria, we demonstrate that for all bounded value distributions, the utilitarian welfare losses of the mechanism as a proportion of the maximum possible welfare tends to zero as the population size
becomes large.

Keywords: social choice, collective decisions, large markets, costly voting, vote trading, Bayes-Nash equilibrium

JEL Classification: C72, D71, D82, H41

Suggested Citation

Lalley, Steven and Weyl, Eric Glen, Nash Equilibria for Quadratic Voting (July 16, 2019). Available at SSRN: https://ssrn.com/abstract=2488763 or http://dx.doi.org/10.2139/ssrn.2488763

Steven Lalley

Department of Statistics, University of Chicago ( email )

Eckhart Hall Room 108
5734 S. University Avenue
Chicago, IL 60637
United States

HOME PAGE: http://galton.uchicago.edu/~lalley/

Eric Glen Weyl (Contact Author)

Microsoft Research New York City ( email )

641 Avenue of the Americas
7th Floor
New York, NY 10011
United States
8579984513 (Phone)

HOME PAGE: http://www.glenweyl.com

RadicalxChange Foundation ( email )

HOME PAGE: http://www.radicalxchange.org

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