Identifying the bandwagon effect in two-round elections

摘要

We propose a new method to test for the existence of the bandwagon effect, the notion that voters are more likely to vote for a given candidate if they expect the candidate to win. Two-round election systems with a large number of single-member districts offer an ideal testing ground because results from the first round provide a better benchmark for voter expectations than any possible alternative measure. Using data from the 2002 and 2006 general elections in Hungary, we find that the lead of a candidate in the first round is magnified by about 10 percent in the second round, controlling for country-wide swings of the electorate between the two rounds and for the behavior of voters of smaller parties. A separate exercise suggests that at least part of the effect is caused by the lower probability of individuals voting in the second round if their preferred candidate is likely to lose by a large margin.