Same Rules, Different Importance: The Impact of Concurrent Elections on Invalid Voting

Although invalid voting takes place at the individual level, previous research found that this phenomenon is affected by various institutional factors such as compulsory voting, the type of the electoral system or the concurrence of elections. In this paper, we focus on the latter feature. In various countries, multiple elections are held simultaneously, placing more pressure on voters. In such an environment, voters might find it complicated to manage their votes, especially if the respective elections differ in their rules and character. On the other hand, it is less known what is the impact on invalid voting in the case of merging two elections with identical rules but of different importance. Our paper aims to fill this gap by focusing on the case of Slovakia. In 2022 the country joined the regional and municipal elections. In both elections, the same rules apply, and the voters select the head of the constituency and its collective assembly, thus casting four separate votes. To identify the impact of merging these two elections, we analyse the share of invalid votes in all 2,926 municipalities. We find that joining the elections had a negligible impact on the number of invalid votes in the more important, i.e., municipal elections. On the other hand, we find that the share of invalid votes increased substantially in the less important, i.e., regional elections, in the case of both the head of the region and the collective regional assembly elections. Moreover, we show that this effect is larger in constituencies with more candidates and seats. In sum, we show that merging two otherwise identical elections of various importance supports the turnout in the less important competition but at the expense of the share of valid votes.