Turnout, party system diversity and left-of-centre parties: explaining turnout through the strength of left-of-centre parties

Abstract

In the last 50 or so years, observers have noted with concern declining rates of voter turnout in many democracies. There has also been a perceived narrowing of ideological diversity in many party systems, with, in particular, many parties on the left moving towards the centre. However, extant literature on turnout and party systems has realized only mixed and often contrary results. By replacing poorly performing aggregate measures of polarization and number of parties with a novel measure of left party strength, a consistent association with turnout is uncovered, alongside clearer conceptualization of how ideological diversity affects turnout. Findings show that measures of party systems that capture the ideological strength and position of left parties have a significant and substantial positive association with voter turnout outperforming more commonly used aggregate measures of party systems.