My research both theoretically and empirically asks which factors shape political competition in democracies. For example, why do some countries have more political parties than others, and why do ethnic issues only sometimes appear on the political agenda? These research questions are important to comparative politics because political competition in turn shapes both public policy and the character of the democratic process. I am currently working on a book manuscript that is very loosely based on my dissertation. This book explores how large-scale changes in society shape political competition, and how political institutions intervene in the process. Israel and the United States are the two case studies. I am also currently working on several articles.

Publications
What Moves Parties? The Role of Public Opinion and Global Economic Conditions in Western Europe (with James Adams and Andrea Haupt). 2009. Comparative Political Studies 42 (5). Forthcoming. || Supplemental Materials

Social Cleavages and the Number of Parties: How the Measures You Choose Affect the Answers You Get. 2008. Comparative Political Studies 41 (11). Forthcoming.|| Supplemental Materials || Replication Data (tab-delimited text file) || Replication Data Codebook

Electoral Rules and the Size of the Prize: How Political Institutions Shape Presidential Party Systems (with Allen Hicken). 2008. Journal of Politics 70 (4). Forthcoming. || Supplemental Materials || Replication Data and Codebook coming soon

WhatIf: R Software for Evaluating Counterfactuals (with Gary King and Langche Zeng). 2006. Journal of Statistical Software 15 (4).

Working Papers
Dimensionality and the Number of Parties in Legislative Elections || Supplemental Materials

Presidents and Parties: How Presidential Elections Shape Coordination in Legislative Elections (with Allen Hicken) || Supplemental Materials

Presidents, Powers and Parties (with Allen Hicken) || Supplemental Materials coming soon

Dissertation
Social Cleavages, Political Institutions, and Party Systems: Putting Preferences Back into the Fundamental Equation of Politics

Statistical Software and Related
WhatIf (with Gary King and Langche Zeng)