Same institutions, same outcomes? Comparing the effect of electoral competition on the level of concentration of votes

Abstract The purpose of this paper is to identify the effect of electoral district magnitude on the spatial concentration of votes. Usually, district magnitude is a proxy for intraparty electoral competition, which incentivizes the personal vote. Studies about Brazil and other countries have considered the personal vote an explanation for the regional concentration of votes. However, the difficulty in directly identifying the concentration levels still remains—even though the districts possess different magnitudes—because the concentration levels of different candidates must not be directly compared. Nevertheless, the electoral simultaneity of the federal and the state legislative elections offers a quasi-experimental case for the effect of different magnitudes over votes’ spatial concentration, controlling for the variation of disputed seats over time. The data ranges from 1998 to 2010 and results indicate the magnitudes lead to the regional concentration of votes, confirming theoretical expectations.