Decomposing the Sources of Electoral Support for LDP Representatives1

In this paper we use a research design that exploits unique features of Japanese elections to estimate and decompose the incumbency advantage in Japan’s Lower House elections. Like some existing related studies we also use repeated observations on the same candidates to account for unobserved factors that remain constant across observations. We find evidence that much of incumbent LDP representatives’ electoral advantage is due to their being higher quality than the average open seat candidate. We find no evidence that LDP representatives receive a direct office holder benefit. In fact, LDP candidates who lose one election and rerun in the subsequent election are found to receive an electoral advantage. This rerun benefit does not appear to be driven by the distribution of inter-governmental transfers.