After months of examining data from more than 2,800 surveys, a task force of polling experts has failed to reach unequivocal explanations about why polls went awry in last year’s U.S. presidential election. While the inconclusive result was unsatisfying, the task force report released last week has value in providing reminders, explicit and otherwise, about the prominence, complexities and vulnerabilities of election polls in presidential campaigns.
The report, commissioned by the American Association for Public Opinion Research, an industry organization known by the acronym AAPOR, noted that collectively the performance of national pre-election polls in the 2020 presidential race was the worst in 40 years.
Discrepancies between poll results and vote outcomes were even greater, the report noted, in many down-ticket races in 2020.
Specifically, polls overall underestimated popular vote support for then-President TrumpDonald TrumpRonny Jackson, former White House doctor, predicts Biden will resign McCarthy: Pelosi appointing members of Jan. 6 panel who share ‘pre-conceived narrative’ Kinzinger denounces ‘lies and conspiracy theories’ while accepting spot on Jan. 6 panel MORE, as well as for Republican gubernatorial and U.S. Senate candidates.
Polls were accurate in pointing to Joe BidenJoe BidenHouse Republican calls second bout of COVID-19 ‘far more challenging’ Conflicting school mask guidance sparks confusion Biden: Pathway to citizenship in reconciliation package ‘remains to be seen’ MORE’s winning the popular vote for president, but the outcome was closer than what polls had indicated. Biden’s popular vote advantage over Trump was 4.5 percentage points. But polls in the closing two weeks of the campaign underestimated Trump’s support by 3.9 points nationally and by 4.3 points in state-level polls, the task force reported.
It was vexing that the task force said it could not determine precisely what factors gave rise to the sharp discrepancies — a finding that will do little to mitigate the wariness and skepticism that run deep in the United States about election polling.
Despite its lack of definitive conclusions, the report underscored how challenging election polling can be, and how surveys can be distorted by any number of variables, including uneven response rates among Republicans and Democrats.
The report also offered an implicit reminder that polling errors can vary markedly and do not spring from a common template. In that sense, they are akin to Tolstoy’s observation that unhappy families are unhappy in their own way. Errant polls likewise tend to err in their own way.
The 2020 polling embarrassment was no rerun of that of 2016, when wayward polls in key states upended confident predictions that Hillary ClintonHillary Diane Rodham ClintonBiden flexes presidential muscle on campaign trail with Virginia’s McAuliffe Shontel Brown gaining ground against Nina Turner in Ohio: poll Biden hits trail for McAuliffe in test of his political brand MORE would defeat Donald Trump handily. On the eve of the 2016 election, for example, HuffPost’s polls-based forecast gave Clinton a 98.2 percent chance of winning the election and declared that Trump had “essentially no path to an Electoral College victory.” Trump won by 304 electoral votes to 227.
Adjustments that pollsters made following the 2016 surprise — notably, to make sure their data included views of non-college-educated white voters who heavily supported Trump — failed to produce accuracy in 2020. “We made all the corrections that we were supposed to make for the 2016 issues, or at least we thought we did, and it didn’t necessarily help us,” one media pollster said at AAPOR’s conference in May.
The 2020 polling error may have been attributable to some Republican voters’ unwillingness to participate in…