Age, period and cohort effects in a dealigned electorate: comparing late deciders and vote switchers

Whereas many advanced democracies experience a long-term process of dealignment, the impact of age, period and cohort on late deciders and vote switchers is still unclear. In addition, extant research fails to systematically examine the determinants that account for the time of vote decision compared to explanations of vote change at the individual level. Drawing on pooled data that include election surveys for Portuguese legislative elections held between 2002 and 2019, this study analyses the impact of age, period and cohort on late deciders and vote switchers. The findings indicate that age has a significant impact on both phenomena, while period effects are important only for the time of vote decision. Finally, the lack of partisan identities and short-term factors, in particular ambivalence towards the main party leaders, are relevant for explaining electoral indecision and inter-election volatility.