Replication Data for: “No Sorting, No Advantage: Regression Discontinuity Estimates of Incumbency Advantage in Japan”

While the existing literature has identified a sizable incumbency advantage in single-member district (SMD) races in developed democracies, we argue that some political and institutional contexts of Japan's Lower House elections would undermine the incumbency advantage. Our regression discontinuity (RD) analysis indeed shows little advantage, and further examination suggests this as largely due to the “best-loser” provision in Japan's mixed-member system, which gives a loser of SMD competition a chance to be a “resurrected” incumbent. We also show no evidence of sorting – i.e., systematic difference between bare winners and bare losers – in close SMD races and thus add further evidence to support the methodological argument that the election RD analysis is a viable and promising research design.

现有学术研究已证实，发达民主国家的单议席选区（single-member district, SMD）选举中存在显著的在位者优势（incumbency advantage）。本文认为，日本众议院选举的部分政治与制度语境会削弱这一在位者优势。我们开展的断点回归（regression discontinuity, RD）分析确实未发现显著的在位者优势，进一步的考察表明，这一结果主要源于日本混合选举制（mixed-member system）中的"最佳落选者"条款（best-loser provision）——该条款允许单议席选区选举的落败者以"复活"在位者（resurrected incumbent）身份获得席位。本文还证实，在竞争激烈的单议席选区选举中，险胜候选人与险败候选人之间不存在系统性差异，即未发现分选效应（sorting），从而为"选举断点回归分析是一种可行且颇具前景的研究设计"这一方法论论点补充了新的实证依据。