A Flexible Measure of Voter Polarization

This paper introduces a definition of ideological polarization of an electorate around a particular central point. By being flexible about the location or width of the center, this measure enables the researcher to analyze polarization around any point of interest. The paper then applies this approach to US voter survey data between 2004 and 2020, showing how polarization between right-of-center voters and the rest of the electorate was increasing gradually, while polarization between left-wingers and the rest was originally constant and then rose steeply. It also shows how, following elections, polarization around left-wing positions decreased while polarization around right-wing positions increased. Furthermore, the paper shows how this measure can be used to find cleavage points around which polarization changed the most. I then show how ideological polarization as defined here is related to other phenomena, such as affective polarization and increased salience of divisive issues.