Representative democracy bundles many issue positions into party manifestos, and voters ultimately make a single choice between those bundles. That single-choice outcome can hide voters' multidimensional policy preferences. This study uses a conjoint experiment based on real party manifestos from Japan's 2014 House of Representatives election to recover those hidden preferences and to show how voters evaluate whole manifestos.
📊 How the Study Was Designed
- Conjoint experiment that presented respondents with hypothetical manifestos created from actual party positions in Japan's 2014 House of Representatives election.
- Respondents chose between juxtaposed sets of issue positions (manifestos), producing choices that reveal how individual issue positions affect holistic evaluations.
- The design permits estimating: the effect of specific positions on manifesto assessments, heterogeneity in preferences across respondent subgroups, and a popularity ranking of manifestos.
🔍 Key Findings
- Specific policy positions produce measurable changes in voters' overall assessments of manifestos.
- Substantial heterogeneity exists: different subgroups prioritize different issues, producing varied manifesto evaluations.
- The popularity ranking derived from respondents' choices shows which bundles of policies are most and least appealing.
- Importantly, revealed multidimensional preferences diverge from the common portrayal of the 2014 election as conferring a clear policy mandate on the Liberal Democratic Party.
📌 Why It Matters
- Inferring public opinion or a ‘‘policy mandate’’ solely from election outcomes can be misleading when voters face multidimensional choices.
- This approach shows how conjoint analysis using real manifestos can uncover nuanced voter preferences, offering a clearer picture for scholars, journalists, and policymakers about what elections actually reveal.
