
进入中期选举之际,所有关注美国政治的人都在问同一个问题:民调是否准确,还是说会再次低估共和党?结果两者皆非。这一次,民调低估的是另一种选民:民主党人。
Heading into the midterms, everyone who follows American politics had the same question: Were the polls correct, or would they underestimate Republicans once again? The answer turned out to be neither. This time around, the polls undercounted a different kind of voter: Democrats.
根据《Silver Bulletin》的民调平均值,民主党有望以九个百分点的优势赢得美国众议院普选票,并在唐纳德·特朗普以两位数优势获胜的几个州以微弱优势翻盘几个参议院席位。全国各地的民主党选民看到这些数字后,都在为失望做准备。他们记得2016年(平均低估特朗普约三个百分点)和2024年(同样低估)的民调失误,并相信自己可能正在目睹另一场“蓝色海市蜃楼”。
According to the Silver Bulletin polling averages, Democrats were on track to win the U.S. House popular vote by nine points and narrowly flip a few Senate seats in states that Donald Trump had won by double digits. Democratic voters across the country saw these numbers and braced for disappointment. They remembered the polling misses of 2016 (which underestimated Trump by about three points on average) and 2024 (which did too) and believed that they could be watching another blue mirage.
事实上,即使是今年看似令人难以置信的民调数字,最终也被证明显著低估了民主党的实力。民主党现在预计将以13个百分点的优势赢得众议院普选票,这是50年来最大的此类胜利。与某些州的偏差相比,这四个百分点的全国性民调误差显得微不足道。在南卡罗来纳州,民调平均低估民主党候选人五个百分点;在密西西比州,低估七个百分点;在得克萨斯州、佐治亚州和北卡罗来纳州,低估九个百分点。结果,原本预计将是民主党大获全胜的夜晚,变成了一场具有历史规模的溃败。
In fact, even this year’s seemingly incredible poll numbers turned out to significantly understate Democrats’ strength. Democrats are now expected to win the House popular vote by 13 points, the largest such victory in 50 years. And that four-point national polling error was small compared with the miss in certain states. In South Carolina, polls underestimated the Democratic candidate by five points on average; in Mississippi, by seven; in Texas, Georgia, and North Carolina, by nine. As a result, what was already expected to be a great night for Democrats turned into a rout of historic proportions.
民调工作本就艰难,且愈发困难。美国人过去习惯可靠地回应调查。如今,仅仅找到愿意接听电话的人就是一场艰难的战役。随着回应率下降,民调机构接触到具有代表性的选民样本的能力也随之减弱。2016年,民调机构低估了特朗普在无大学学历白人选民中的支持率,因为他们无法调查到足够多的此类选民。
Polling is hard and getting harder. Americans used to reliably answer surveys. Now simply finding people willing to pick up the phone is an uphill battle. As response rates have declined, so has pollsters’ ability to reach a representative sample of the electorate. In 2016, pollsters underestimated Trump’s support among white voters without a college degree because they couldn’t poll enough of them.
在 2020 年,行业努力更广泛地触及选民。尽管如此,民调仍更低估了特朗普。民调人员认为,即使现在已覆盖到正确的教育群体,他们仍可能错过某些人格类型,而这些人格类型更倾向于支持特朗普。还需要做更多判断。为了 2024 年,民调人员特意确保样本中包含足够的 2020 年特朗普选民。那也没有奏效——他们又一次低估了特朗普。
In 2020, the industry made a concerted effort to reach more of those voters. And yet the polls underestimated Trump by even more. Pollsters reasoned that even if they were now reaching the right educational groups, they must be missing certain personality types that were disproportionately likely to prefer Trump. More judgment calls needed to be made. Ahead of 2024, pollsters made a point of ensuring that their samples included enough 2020 Trump voters. That didn’t do the trick either—they managed to underestimate Trump yet again.
在这一轮中,民调人员推出了更多定制化方案。在他们共同开展的民调中,《纽约时报》和锡耶纳学院制定了排除被认为不具代表性的受访者的方法——例如,农村白人大学城居民可能与其他农村白人选民不同——并开始根据受访者的名字听起来多像共和党人或他们驾驶的汽车来加权。YouGov 投入资源,确保不仅有来自紫色社区的选民,还有来自深红色社区的选民。
This cycle, pollsters introduced even more bespoke solutions. In their jointly run polls, The New York Times and Siena College devised ways to discount respondents they deemed unrepresentative—rural white college-town residents, for example, might not be like other rural white voters—and started weighting respondents based on how Republican their name sounds or what car they drive. YouGov put resources into making sure that it had enough voters from not just purple neighborhoods but deep-red ones too.
它还引入了新的投票率建模方式,区分“严格”与“宽松”的可能投票者定义,因为“严格”可能投票者可能只包括最活跃的选民,而不包括那些更难接触、比例上更支持特朗普且可能仍会投票的选民。
It also introduced new ways to model turnout, differentiating between a “strict” definition of likely voters and a “loose” one, because “strict” likely voters might include only the most engaged ones, and not the hard-to-reach ones who disproportionately support Trump and might still vote.
民调人员是科学家,但他们也是人。他们尽力避免偏见,却仍然存在偏见。他们在本轮所做的调整确实是为了最大化调查的准确性,但他们还有另一个目标:不再被“烧”一次。变化的目的并非不显著,旨在避免过度高估民主党人的机会。如果民调人员在 2024 年使用了这些新技术,他们本可以更接近最终结果。周末,《纽约时报》首席政治分析师 Nate Cohn 写道,该报在 2024 年之后的加权技术使其民调对共和党更有利。
Pollsters are scientists, but they are also humans. They do their best to avoid biases, and yet they have them anyway. The adjustments they made this cycle were in service of maximizing the accuracy of their surveys, yes, but they also had another goal: not getting burned again. The changes were unsubtly aimed at not overrating the Democrats’ chances. If pollsters had used these new techniques in 2024, they would have more closely predicted the final result. Nate Cohn, the chief political analyst for The New York Times, wrote over the weekend that the paper’s post-2024 weighting techniques made its polls look better for Republicans.
在过去的两次中期选举中,2018 年和 2022 年,民调机构几乎没有系统性误差地预测了最终结果。 这很可能是因为对民调员来说最难以触及的选民往往在中期选举中不去投票,而此时总统并未出现在选票上。 通过努力纠正 2024 年出现的问题,民调员实际上是在解决今年不太可能出现的挑战。
In the past two midterms, in 2018 and 2022, pollsters nailed the final result with little systematic error. That’s probably because the voters that are hardest for pollsters to reach tend not to show up to vote in midterm elections, when the president isn’t on the ballot. By working hard to correct what went wrong in 2024, pollsters were solving for challenges that were less likely to come up this year anyway.
即便如此,从某种意义上说,民调员实现了他们的目标:他们没有被隐藏的特朗普选民击败。 相反,民调的走势相反,尤其是在某些少数族裔群体方面。 在选举后不久就跟踪不同群体的投票情况很困难,但据《时代》今年部署的一种复杂新模型显示,德州的西班牙裔选民向民主党倾斜了 42 个百分点——比民调预测多 10 个百分点。
Even so, in one sense, pollsters accomplished their goal: They were not burned by hidden Trump voters. Instead, the polls moved in the opposite direction, especially when it came to some minority groups. Tracking how different groups voted so soon after an election is difficult, but according to a sophisticated new model deployed this year by the Times, Hispanic voters in Texas swung toward Democrats by 42 points—10 more points than the polls predicted.
全国范围内,黑人选民对民主党的支持被低估了类似的幅度。 根据民调,民主党本应在摇摆州赢得年轻男性选民九个百分点,尽管在 2024 年他们失去了这些选民。 结果,民主党似乎在全国范围内以 24 个百分点赢得了该人口群体。
Black voters’ nationwide support for Democrats was underrated by a similar amount. According to the polls, Democrats were set to win young men in battleground states by nine points after losing them badly in 2024. In the end, Democrats seem to have won that demographic nationwide by 24 points.
在选举民调的漫长历史中,误差往往没有偏向任何一方。 然而,从 2016 年到 2024 年,它们确实偏向了一方。 现在它们不再偏向,或许是特朗普时代结束的又一个迹象。
In the long history of electoral polling, errors have not tended to favor one party over the other. Then, from 2016 to 2024, they did. That they no longer do is perhaps one more sign that the Trump era is ending.