Identifying the Effect of Election Closeness on Voter Turnout: Evidence from Swiss Referenda
Journal of the European Economic Association · 2023 · Leonardo Bursztyn、Davide Cantoni、Patricia Funk、Felix Schönenberger、Noam Yuchtman
中文摘要
我们利用针对瑞士事关重大的联邦公投的全国性民调结果精确到日的发布时间，以及一个有关日内瓦州每日邮寄投票的新数据集，提供了预期的选举势均力敌程度对选民投票率具有因果效应的证据。采用事件研究设计，我们发现，发布显示双方支持率更为接近的民调会导致选民投票率在发布后立即大幅上升，而发布前的投票率水平或趋势不存在差异。我们提供的证据表明，民调通过提供信息，塑造人们对选举势均力敌程度的判断，从而影响投票率。显示双方支持率接近的民调，在报纸对其报道最多的地方产生的效应最大；此外，引入民调在政治上不具代表性的市镇产生的效应显著更大，在这些市镇，当地可获得的有关选举势均力敌程度的信号与全国层面势均力敌程度的相关性较低。随后，我们提供证据表明，显示双方支持率接近的民调具有异质性效应，其中的不对称效应使处于劣势的一方获得更高的得票份额。我们估计的效应量级足够大，足以在合理的反事实情景下逆转事关重大的选举结果。
Abstract
Abstract We provide evidence of a causal effect of anticipated election closeness on voter turnout, exploiting the precise day-level timing of the release of Swiss national poll results for high-stakes federal referenda, and a novel dataset on daily mail-in voting for the canton of Geneva. Using an event study design, we find that the release of a closer poll causes voter turnout to sharply rise immediately after poll release, with no differential pre-release turnout levels or trends. We provide evidence that polls affect turnout by providing information shaping beliefs about closeness. The effects of close polls are the largest where newspapers report on them most; and, the introduction of polls had significantly larger effects in politically unrepresentative municipalities, where locally available signals of closeness are less correlated with national closeness. We then provide evidence that the effect of close polls is heterogeneous, with an asymmetric effect leading to a higher vote share for the underdog. The effect sizes we estimate are large enough to flip high-stakes election outcomes under plausible counterfactual scenarios.