A general model of abstention under compulsory voting

Invalid voting and absenteeism are alternative sources of abstention under compulsory voting. Previous research failed to systematically study the mechanisms behind each form of non-voting and the relationships between them. We develop an analytical framework and an empirical strategy to jointly examine invalid voting and absenteeism in Brazil, the world's largest democracy with mandatory voting. Using Bayesian inferential methods and analyzing both individual and district-level data, we show that less educated and politically knowledgeable citizens are less likely to vote and, when they do, they are typically unable to successfully complete their ballot. Unlike absenteeism, invalid voting also has a political dimension reflecting voters’ disenchantment with elections and democratic performance. Both sources of abstention coexist and, together, undermine electoral participation