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Ideological Congruence and Electoral Institutions


  • We would like to thank Jason Barabas, André Blais, Charles Barrilleaux, Bill Berry, William Roberts Clark, Sean Ehrlich, Justin Esaray, Lawrence Ezrow, Sona Nadenichek Golder, Brad Gomez, Mark Hallerberg, Amie Kreppel, Michael D. McDonald, Will Moore, G. Bingham Powell, Christopher Reenock, David Siegel, Jeffrey Staton, two anonymous reviewers, members of the Political Institutions Working Group at Florida State University, as well as audiences at the University of Florida, the 2006 annual meeting of the American Political Science Association, and the 2007 annual meeting of the Midwest Political Science Association for helpful comments on earlier versions of this article. The data and all computer code necessary to replicate the results and figures in this analysis will be made publicly available at on publication. STATA 10 was the statistical package used in this study.

Matt Golder is Assistant Professor of Political Science, Florida State University, 540 Bellamy Building, Tallahassee, FL 32306-2230 ( Jacek Stramski is a Graduate Student in the College of Law, Florida State University, 425 W. Jefferson St., Tallahassee, FL 32306-1601 (


Although the literature examining the relationship between ideological congruence and electoral rules is quite large, relatively little attention has been paid to how congruence should be conceptualized. As we demonstrate, empirical results regarding ideological congruence can depend on exactly how scholars conceptualize and measure it. In addition to clarifying various aspects of how scholars currently conceptualize congruence, we introduce a new conceptualization and measure of congruence that captures a long tradition in democratic theory emphasizing the ideal of having a legislature that accurately reflects the preferences of the citizenry as a whole. Our new measure is the direct counterpart for congruence of the vote-seat disproportionality measures so heavily used in comparative studies of representation. Using particularly appropriate data from the Comparative Study of Electoral Systems, we find that governments in proportional democracies are not substantively more congruent than those in majoritarian democracies. Proportional democracies are, however, characterized by more representative legislatures.