Original
Universal Mail Ballot Delivery Boosts Turnout: The Causal Effects of Sending Mail Ballots to All Registered Voters
Abstract
Prior to the COVID-19 pandemic, some American states had transitioned to universal voting by mail, where all registered voters receive a mail ballot. But due to the pandemic, universal voting by mail was suddenly used in a larger number of states in 2020. Here we study a unique situation in which registered voters in some legislative districts in Los Angeles County were subjected to universal voting by mail in the March 2020 primary. Using difference in-differences and geographic boundary-based designs on individual-level records, we take advantage of this within-jurisdiction situation to estimate the causal effects of universal voting by mail on voter turnout and on who votes. Our results indicate that voter turnout increased by 3 to 4 percentage points for voters who do not automatically receive a mail ballot, and the increase is generally larger for registered partisan voters than those without a party affiliation.
中文
全民邮寄选票递送提升投票率：向所有登记选民寄送邮寄选票的因果效应
摘要
在COVID-19大流行之前，美国一些州已转向普遍邮寄投票，即所有登记选民都会收到一张邮寄选票。但由于大流行，2020年有更多州突然采用普遍邮寄投票。本文研究了一个独特情形：在2020年3月初选中，洛杉矶县部分立法选区的登记选民被纳入普遍邮寄投票。利用个体层面记录上的双重差分设计和基于地理边界的设计，我们借助这一辖区内部情形，估计普遍邮寄投票对选民投票率及投票者构成的因果效应。结果表明，对于不能自动收到邮寄选票的选民，投票率提高了3至4个百分点，且这一增幅对有党派归属的登记选民通常大于无党派归属选民。
关键词
普遍邮寄投票、邮寄选票、投票率、因果效应、双重差分、地理边界设计、洛杉矶县、党派归属