Polarization and ideology: Partisan sources of low dimensionality in scaled roll call analyses


Journal Article

In this article, we challenge the conclusion that the preferences of members of Congress are best represented as existing in a low-dimensional space. We conduct Monte Carlo simulations altering assumptions regarding the dimensionality and distribution of member preferences and scale the resulting roll call matrices. Our simulations show that party polarization generates misleading evidence in favor of low dimensionality. This suggests that the increasing levels of party polarization in recent Congresses may have produced false evidence in favor of a lowdimensional policy space. However, we show that focusing more narrowly on each party caucus in isolation can help researchers discern the true dimensionality of the policy space in the context of significant party polarization. We re-examine the historical roll call record and find evidence suggesting that the low dimensionality of the contemporary Congress may reflect party polarization rather than changes in the dimensionality of policy conflict.

Full Text

Duke Authors

Cited Authors

  • Aldrich, JH; Montgomery, JM; Sparks, DB

Published Date

  • January 1, 2014

Published In

Volume / Issue

  • 22 / 4

Start / End Page

  • 435 - 456

Electronic International Standard Serial Number (EISSN)

  • 1476-4989

International Standard Serial Number (ISSN)

  • 1047-1987

Digital Object Identifier (DOI)

  • 10.1093/pan/mpt048

Citation Source

  • Scopus