The mayor's advantage: Causal evidence on incumbency effects in German mayoral elections

- I study the party incumbency effect of mayors in German municipalities.
- The study focuses on causal analysis using a regression discontinuity design.
- The incumbency is found to be sizable and comparable to effects in other countries.
- Due to exceptionally rich data, I can also report interesting heterogeneous effects.

This paper provides empirical evidence on the party incumbency advantage in mayoral elections in Germany. Using a regression discontinuity design on a data set of about 25,000 elections, I estimate a causal incumbency effect of 38-40 percentage points in the probability of winning the next election. Studying the mechanisms behind this effect, I show that the electoral advantage is larger for full-time mayors, increasing in municipality size, independent of the specific partisanship of the mayor and constant between 1945 and 2010. Moreover, it increases with local spending hikes and it is independent of municipal debt.