a1 University of Rochester
a2 University of Rochester
Although democracy is a key concept in political science, debate continues over definitions and mechanisms. Bueno de Mesquita, Smith, Siverson, & Morrow (2003) make the important claim that most of democracy's effects are in fact due to something conceptually simpler and empirically easier to measure than democracy: the size of the minimum winning coalition that selects the leader. The argument is intuitively appealing and supported by extensive data analysis. Unfortunately, the statistical technique they use induces omitted variable bias into their results. They argue that they need to control for democracy, but their estimation procedure is equivalent to omitting democracy from their analysis. When we reestimate their regressions controlling for democracy, most of their important findings do not survive.
A full version of this paper is available at http://www.rochester.edu/College/PSC/clarke/. An early version was given at the Watson Center for Conflict and Cooperation at the University of Rochester, October 2006. We thank the editor, three anonymous reviewers, Muhammet Bas, Bear Braumoeller, Hein Goemans, Jon Hanson, Gretchen Helmke, Elena McLean, Bonnie Meguid, David Primo, Martin Steinwand; and especially Bing Powell and John Jackson for helpful comments and advice. We also thank Bruce Bueno de Mesquita, Alastair Smith, Randy Siverson, and Jim Morrow for sharing their data and code. All errors remain our own.