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Democratic Compromise: A Latent Variable Analysis of Ten Measures of Regime Type

Published online by Cambridge University Press:  04 January 2017

Daniel Pemstein*
Center for the Study of Democratic Institutions, Vanderbilt University, PMB 407712, 2301 Vanderbilt Place, Nashville, TN 37240-7712
Stephen A. Meserve
Department of Political Science, University of Illinois at Urbana-Champaign, 240 Computer Applications Building, 605 East Springfield Ave., Champaign, IL 61820. e-mail:
James Melton
Economics and Institutional Change, IMT Institute for Advanced Studies, Piazza San Ponziano 6, 55100 Lucca, Italy. e-mail:
e-mail: (corresponding author)
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Using a Bayesian latent variable approach, we synthesize a new measure of democracy, the Unified Democracy Scores (UDS), from 10 extant scales. Our measure eschews the difficult—and often arbitrary—decision to use one existing democracy scale over another in favor of a cumulative approach that allows us to simultaneously leverage the measurement efforts of numerous scholars. The result of this cumulative approach is a measure of democracy that, for every country-year, is at least as reliable as the most reliable component measure and is accompanied by quantitative estimates of uncertainty in the level of democracy. Moreover, for those who wish to continue using previously existing scales or to evaluate research performed using those scales, we extract information from the new measure to perform heretofore impossible direct comparisons between component scales. Specifically, we estimate the relative reliability of the constituent indicators, compare the specific ordinal levels of each of the existing measures in relationship to one another and assess overall levels of disagreement across raters. We make the UDS and associated parameter estimates freely available online and provide a detailed tutorial that demonstrates how to best use the UDS in applied work.

Research Article
Copyright © The Author 2010. Published by Oxford University Press on behalf of the Society for Political Methodology 


Authors' note: The authors are listed in reverse alphabetical order, indicating equal contribution to the article. The authors would like to thank Bill Bernhard, Jose Antonio Cheibub, Josh Clinton, Zach Elkins, Brian Gaines, Jim Kuklinski, Kevin Quinn, seminar participants at the University of Illinois, participants at the 24th Annual Meeting of the Society for Political Methodology, our reviewers, and the editors of Political Analysis for helpful comments. Supplementary materials for this article are available on the Political Analysis Web site.


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