Replication data for: Voter Turnout and the National Election Studies

Though the overreporting of voter turnout in the National Election Study (NES) is widely known, this article shows that the problem has become increasingly severe. The gap between NES and official estimates of presidential election turnout has more than doubled in a nearly linear fashion, from 11 points in 1952 to 24 points in 1996. This occurred because official voter turnout fell steadily from 1960 onward, while NES turnout did not. In contrast, the bias in House election turnout is always smaller and has increased only marginally. Using simple bivariate statistics, I find that worsening presidential turnout estimates are the result mostly of declining response rates rather than instrumentation, question wording changes, or other factors. As more peripheral voters have eluded interviewers in recent years, the sample became more saturated with self-reported voters, thus inflating reported turnout.

尽管全国选举研究（National Election Study, NES）中选民投票率虚报的问题早已广为人知，但本文证实该问题正愈发严峻。全国选举研究与官方统计的总统选举投票率差距已近乎线性扩大，从1952年的11个百分点增至1996年的24个百分点。造成这一差距持续拉大的原因在于，1960年起官方统计的选民投票率持续走低，而全国选举研究的投票率数据却未出现相应下滑。与之形成鲜明对比的是，众议院选举投票率统计的偏差始终更小，且仅出现小幅上升。通过简单的双变量统计分析，本文发现总统选举投票率估算偏差加剧的主要诱因是回复率下降，而非调查工具、问题措辞调整或其他因素。近年来，越来越多的边缘选民避开了访谈，致使样本中自报投票者的占比愈发偏高，进而推高了报告的投票率数值。