Concurrency of elections is a widely used tool to increase turnout. However, this turnout increase is likely not outcome-neutral if some voters attribute more importance to one of the elections compared to the other. We theorize coattail effects and electoral system effects that should occur in this setting. Drawing on a unique case of quasi-random variation in the timing of local executive and legislative elections in Germany, we show that concurrent elections lead to an increase in turnout. Thereby, in line with our theoretical argument, concurrency of local executive elections increases council votes for the incumbent mayor's party and for centrist parties more generally. Additionally, concurrent elections consolidate party system and political power through more single-party majorities in councils, less fragmentation and greater alignment of executive leadership and legislative majority. Our theoretical argument and empirical results thus serve to explain divergent findings in the literature on turnout effects.
Coattails and spillover-effects: Quasi-experimental evidence from concurrent executive and legislative elections
