Strict ID Laws Don’t Stop Voters: Evidence from a U.S. Nationwide Panel, 2008–2018
中文摘要
美国各州日益要求选民在投票时出示身份证件——此举表面上旨在遏制舞弊，却引发了对选择性剥夺投票权的质疑。我们对一个包含16亿个观测值、覆盖2008—2018年的面板数据集采用双重差分设计，发现这些法律对选民登记或投票率均无负面影响，无论是总体而言，还是对按种族、性别、年龄或党派归属界定的任何群体而言。大量不同设定均支持这一结果。我们要求最高的设定控制了州、年份和选民固定效应，以及州和选民层面随时间变化的控制变量。基于这一设定，我们得到这些法律对总体选民登记率和投票率影响的点估计均为−0.1个百分点（95%置信区间分别为[−2.3，2.1个百分点]和[−3.0，2.8个百分点]），对非白人选民相对于白人选民投票率影响的点估计为+1.4个百分点（95%置信区间为[−0.5，3.2个百分点]）。选民投票率未受负面影响，不能归因于选民对这些法律的反制反应；这种反应通过竞选捐款和自我报告的政治参与来衡量。然而，非白人选民被竞选团队联系的可能性提高了4.7个百分点，这表明政党的动员可能抵消了这些法律对少数族裔参政所产生的较小影响。最后，严格的身份证件要求对实际或感知到的舞弊均无影响。总体而言，我们的研究结果表明，改善选举的努力或许更应投向其他改革。
Abstract
Abstract U.S. states increasingly require identification to vote—an ostensible attempt to deter fraud that prompts complaints of selective disenfranchisement. Using a difference-in-differences design on a panel data set with 1.6 billion observations, 2008–2018, we find that the laws have no negative effect on registration or turnout, overall or for any group defined by race, gender, age, or party affiliation. These results hold through a large number of specifications. Our most demanding specification controls for state, year, and voter fixed effects, along with state and voter time-varying controls. Based on this specification, we obtain point estimates of −0.1 percentage points for effects both on overall registration and turnout (with 95% confidence intervals of [−2.3; 2.1 percentage points] and [−3.0; 2.8 percentage points], respectively), and +1.4 percentage points for the effect on the turnout of nonwhite voters relative to whites (with a 95% confidence interval of [−0.5; 3.2 percentage points]). The lack of negative impact on voter turnout cannot be attributed to voters’ reaction against the laws, measured by campaign contributions and self-reported political engagement. However, the likelihood that nonwhite voters were contacted by a campaign increases by 4.7 percentage points, suggesting that parties’ mobilization might have offset modest effects of the laws on the participation of ethnic minorities. Finally, strict ID requirements have no effect on fraud, actual or perceived. Overall, our findings suggest that efforts to improve elections may be better directed at other reforms.