CaltechAUTHORS
  A Caltech Library Service

Standard Voting Power Indexes Don't Work: An Empirical Analysis

Gelman, Andrew and Katz, Jonathan N. and Bafumi, Joseph (2002) Standard Voting Power Indexes Don't Work: An Empirical Analysis. Social Science Working Paper, 1133. California Institute of Technology , Pasadena, CA. (Unpublished) https://resolver.caltech.edu/CaltechAUTHORS:20170802-162810725

[img] PDF (sswp 1133 - Oct. 2002) - Submitted Version
See Usage Policy.

374Kb

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20170802-162810725

Abstract

Voting power indexes such as that of Banzhaf (1965) are derived, explicitly or implicitly, from the assumption that all votes are equally likely (i.e., random voting). That assumption can be generalized to hold that the probability of a vote being decisive in a jurisdiction with n voters is proportional to 1/√n. We test and reject this hypothesis empirically, using data from several different U.S. and European elections. We find that the probability of a decisive vote is approximately proportional to 1/n. The random voting model (or its generalization, the square-root rule) overestimates the probability of close elections in larger jurisdictions. As a result, classical voting power indexes make voters in large jurisdictions appear more powerful than they really are. The most important political implication of our result is that proportionally weighted voting systems (that is, each jurisdiction gets a number of votes proportional to n) are basically fair. This contradicts the claim in the voting power literature that weights should be approximately proportional to √n.


Item Type:Report or Paper (Working Paper)
Related URLs:
URLURL TypeDescription
http://resolver.caltech.edu/CaltechAUTHORS:20140314-120456292Related ItemPublished Version
ORCID:
AuthorORCID
Katz, Jonathan N.0000-0002-5287-3503
Additional Information:Published as Gelman, Andrew and Katz, Jonathan N. and Bafumi, Joseph (2004) Standard Voting Power Indexes Don't Work: An Empirical Analysis. British Journal of Political Science, 34 (4). pp. 657-674.
Group:Social Science Working Papers
Subject Keywords:Banzhaf index, decisive vote, elections, electoral college, Shapley value, voting power
Series Name:Social Science Working Paper
Issue or Number:1133
Record Number:CaltechAUTHORS:20170802-162810725
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170802-162810725
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:79798
Collection:CaltechAUTHORS
Deposited By: Jacquelyn Bussone
Deposited On:02 Aug 2017 23:45
Last Modified:03 Oct 2019 18:24

Repository Staff Only: item control page