EPJ Data Sci. (2020) 9: 32
https://doi.org/10.1140/epjds/s13688-020-00249-4

Regular article

The great divide: drivers of polarization in the US public

¹ Department of Computational Medicine, UCLA, Life Sciences Bldg., Box 951766, Los Angeles, US
² Institute for Theoretical Physics, ETH Zurich, Wolfgang-Pauli-Str. 27, 8093, Zurich, Switzerland
³ Center of Economic Research, ETH Zurich, Zürichbergstrasse 18, 8092, Zurich, Switzerland

^* e-mail: lucasb@ucla.edu

Received: 10 January 2020
Accepted: 28 September 2020
Published online: 28 October 2020

Abstract

Many democratic societies have become more politically polarized, with the U.S. being the main example. The origins of this phenomenon are still not well-understood and subject to debate. To provide insight into some of the mechanisms underlying political polarization, we develop a mathematical framework and employ Bayesian Markov chain Monte-Carlo (MCMC) and information-theoretic concepts to analyze empirical data on political polarization that has been collected by Pew Research Center from 1994 to 2017. Our framework can capture the evolution of polarization in the Democratic- and Republican-leaning segments of the U.S. public and allows us to identify its drivers. Our empirical and quantitative evidence suggests that political polarization in the U.S. is mainly driven by strong political/cultural initiatives in the Democratic party.