Replication Data for: Does Proportionality Increase Turnout? A Study of Adaptation to Oscillating Electoral Systems

Does proportionality increase turnout? This article studies a national electoral reform in early twentieth-century Argentina that was implemented asymmetrically across districts, creating a natural laboratory in which some districts oscillated between electoral systems across elections. Leveraging this unusual variation in a difference-in-differences design, this article shows that a shift from multi-member plurality rules towards a slightly more proportional system ---which removed one-third of the contested seats from the grasp of the dominant party--- led to a four percentage points increase in turnout. An investigation into causal mechanisms indicates that more proportional rules, by increasing the odds that smaller parties obtain seats, promoted strategic party entry and intensified electoral competition (both between and within parties). These findings complement existing quasi-experimental results that focus exclusively on elections in European democracies, confirm that parties are able to adapt immediately to changes in electoral rules, and refute the belief that proportionality does not affect turnout in Latin America.选举比例性能否提升投票率？本文以20世纪初阿根廷的一项全国性选举改革为研究对象，该改革在各选区间不对称推行，由此构建了一个自然实验场景：部分选区在不同选举周期中于多种选举制度间往复切换。本文借助这一罕见的制度差异，采用双重差分法（difference-in-differences）展开分析，结果显示：从多名多数制（multi-member plurality rules）转向略具比例性的选举制度（proportional system）——该制度令执政党无法再掌控三分之一的竞选席位——使得投票率提升了4个百分点。针对因果机制的探究表明，更具比例性的选举规则通过提升小党派获得席位的概率，推动了战略性党派参选，并加剧了党派间与党派内部的选举竞争。本研究的发现补充了此前仅聚焦欧洲民主国家选举的准实验研究成果，证实政党能够迅速适应选举规则的变动，并驳斥了"比例代表制不会影响拉美地区投票率"的观点。