Does the election closeness message increase voter turnout? Evidence from a field experiment in Japan

The calculus of voting indicates that individuals are more likely to vote when they believe their vote could affect the outcome. However, most field experiments examining the effect of perceived election closeness have found no significant effect. This study investigates the causal effect of communicating election closeness through a field experiment conducted in Ashiya, Japan. Japanese city council elections are an ideal setting for this analysis because they are often decided by narrow margins. The results of a field experiment conducted during the 2023 Ashiya City Council election demonstrate that conveying information about past close elections does not significantly increase voter turnout. A post-election survey conducted to explore the mechanisms underlying this result indicated that most voters paid little attention to the content of the postcards distributed during the campaign. These findings indicate that messages emphasizing electoral closeness are insufficient to increase voter turnout. More broadly, the positive association between electoral closeness and turnout found in observational studies may reflect candidates’ mobilization efforts rather than the voters’ perception of closeness. This study also suggests that field experiments using direct mail may underestimate causal effects because voters are likely to overlook the postcards they receive.