Electoral closeness and voter turnout in presidential run-off elections

This article presents the first study of the effects of electoral closeness on voter turnout in presidential run-off elections. Closeness between the leading candidates in the first round should increase turnout in the run-off. Furthermore, since presidential contests are always important elections with high levels of media attention, the direct effect of closeness should be amplified through several mutually reinforcing indirect mechanisms. We test our propositions on an original data set of all popular presidential elections in 16 European democracies, 1965-2024. In line with our expectations, a smaller first-round margin between frontrunner and runner-up is associated with a significant increase in turnout. In contrast, the presence of a strong third-placed candidate decreases it. Furthermore, we show that closeness measured through polls between rounds can explain additional variance in the data. Finally, our analysis of individual elections in five countries suggests further important avenues for research on turnout and double-ballot systems.