Teppei Yamamoto - Associate Professor of Political Science, Massachusetts Institute of Technology
Representative democracy necessitates the aggregation of multiple policy issues by parties into competing bundles of policies, or “manifestos,” which are then evaluated holistically by voters in elections. This aggregation process complicates our understanding of the multidimensional policy preferences underlying a voter’s single choice of a party or candidate. We address this problem with a novel conjoint experiment based on actual party manifestos. By juxtaposing sets of issue positions as hypothetical manifestos and asking respondents to choose one, our study identifies the effects of specific positions on voters’ overall assessment of manifestos, heterogeneity in preferences across popularity ranking of manifestos. We illustrate the approach with a field experiment conducted during Japan’s 2014 House of Representatives election. Our analysis uncovers important discrepancies between voters’ preferences and the portrayal of the election by politicians and the media, underscoring the potential danger of inferring voters’ policy preferences only from election outcomes.