The 2020 Polling Disaster
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As the last presidential election approached, one could sense that something was wrong with the polls. The race felt tighter than the polls indicated, and specifically, Joe Biden’s solid lead in the polls felt less solid than the surveys suggested. As they had in 2016, pollsters appeared on their way to underestimating the vote for Donald Trump. That did not mean Trump was actually leading the race, or that he would win — and in the end, he did not — but that the contest was closer than the polls said.
Now it turns out that feeling was right. And the polls were not only wrong, but more wrong than they had been in decades, including their dismal performance in 2016. A new report from the American Association for Public Opinion Research has found that national election polls overstated Biden’s lead over Trump by 3.9 percentage points. And state-level polls were even worse, overstating Biden’s lead by 4.3 points.
The polls’ performances in statewide races — campaigns for senator and governor — were worse still. There, they overstated the Democratic candidates’ lead by an aver- age of 6 percentage points.
Notice something? The errors went in one direction: Exaggerating support for Democratic candidates. “Whether the candidates were running for president, senator or governor, poll margins overall suggested that Democratic candidates would do better and Republican candidates would do worse relative to the final certified vote,” the report says.
So all those Republicans who said the polls were slant- ed against Trump and the GOP — they were right.
Now, the question is why. Many Republicans will answer that it’s simple — that the polls were just biased. Indeed, don’t ever discount the possibility that pure bias is at work. But a panel of political scientists and polling experts appointed by the AAPOR found that pollsters had managed to avoid repeating the mistake they made in 2016 — undercounting voters without a college degree who voted for Trump. So if that wasn’t the problem in 2020, what was?
The analysts do not think the issue was specifically Trump, or pollsters would have done better on the senators and governors races. They also couldn’t find any specific group of voters that they missed. Instead, they focused on the theory that many Republicans distrust the media and pollsters so much that they would not respond to polling requests. Focusing only on those Republicans who were recep- tive to pollsters gave the polls a skewed view of GOP attitudes.
“That the polls overstated Biden’s support in whiter, more rural and less densely populated states is suggestive (but not conclusive) that the polling error resulted from too few Trump supporters responding to polls,” the report says. “A larger polling error was found in states with more Trump supporters.”
In the end, though, the panel says it cannot definitively determine where pollsters made their mistake. “Identifying conclusively why polls overstated the Democratic-Republican margin … appears to be impossible with the available data,” the report concludes.
The bottom line: The polls were wrong, and they were consistently wrong in one direction, overstating Democratic support and understating Republican support. And the problem wasn’t only about Trump.
That is an extremely troubling conclusion for the millions of Americans who follow politics. Media coverage of big races is often based on a general understanding of who is leading and who is trailing. And that understanding comes from public opinion polls. If a candidate has a 1- point lead over an opponent, for example, the coverage will present the race as virtually tied and highly competitive. If a candidate has a 6-point lead over an opponent, the coverage will present the leader as the dominant figure in the race. That can discourage supporters of the trailing candidate. And it all comes from polls.
And what if the polls are wrong — not just a little wrong, but a lot wrong? Either the polls will be fixed, or we will have to find a different way to cover politics.