Intra-Party Heterogeneity in Policy Preferences and Its Effect on Issue Salience: Evidence from the Comparative Candidates Survey

Abstract

Quantitative research on the positions of political parties and party competition regularly invokes the assumption that parties are unitary actors with homogenous policy preferences. Drawing on Comparative Candidates Survey (CCS) data from 28 elections in 21 developed democracies, we show that candidates often hold quite heterogeneous issue positions and that the extent of this heterogeneity varies significantly across parties and, most interestingly, even within parties across different issue dimensions. In an effort to explore the implications of such intra-party heterogeneity for party strategy and competition, we argue that intra-party heterogeneity and issue salience go together, because parties will emphasize those issues on which intra-party heterogeneity is low. Empirically, we relate our measures of intra-party heterogeneity from the CSS to data on issue salience from the Chapel Hill Expert Survey and the Manifesto Project. Across different issue dimensions and the two salience measures, we consistently find that parties attach lower salience to issues over which they are internally divided.