THE CAUSAL IMPACT OF CLOSENESS ON ELECTORAL PARTICIPATION EXPLOITING THE ITALIAN DUAL BALLOT SYSTEM

Using data from Italian municipal elections from 1993 to 2011, we investigate whether political competition affects electoral turnout. Taking advantage of the dual ballot system adopted for municipalities with more than 15,000 inhabitants, we measure the expected closeness in the second round through the first round electoral results. Thanks to the richness of our dataset we are able to distinguish between valid, blank and invalid ballots and to investigate the effect of closeness on each of these variables, controlling for municipalities’ and candidates’ characteristics and for municipal fixed effects. We also estimate a Heckman selection model to take into account for the non-randomly selected sample. It emerges that closeness strongly increases valid ballots and reduces blank ballots supporting the idea that the expected benefits of voting increase in closer competitions. The effect is much higher in magnitude than that merging when measuring closeness with ex-post electoral results, suggesting a quite relevant endogeneity bias. On the other hand, we do not find any statistically significant effect on invalid ballots.Electoral Turnout, Closeness, Electoral Competition, Blank and Invalid Ballots