(CN) — The polls were wrong. Again.
Joe Biden was up by 10 points or more in surveys taken just before the election by NBC News, the Wall Street Journal, the Economist, CNBC and Quinnipiac. Once ballots were tallied, however, his 3-point lead over Donald Trump in the popular vote is barely better than that of Hillary Clinton in 2016.
The RealClear Politics polling average had Biden winning Florida by about 1 point, but he lost by 3.3. Wisconsin polls had Biden up by 6.7 points; he won by only 0.7. The last five polls in Texas showed Trump winning by about a point, but he won by 6.
And it wasn’t just the presidential race where the polling consistently overestimated Democratic strength. Polls in Senate races were even further off, with surveys in nearly every marquee contest showing Democrats doing far better than they actually did.
In Maine, some 14 polls were taken this year and every single one showed Republican Susan Collins losing. The last three polls before the election showed her behind by 4, 6 and 7 points. She won by almost 9.
In Montana, the last four polls before the election showed Republican Steve Daines winning by about a point. He won by 10.
In South Carolina, three of the six polls taken closest to the election showed the race as a dead heat. Republican Lindsey Graham won by well over 10 points.
And there’s more. Polls significantly overestimated the Democratic vote in key Senate races in Georgia, Michigan, Iowa and North Carolina.
Coupled with the polls’ well-known failure in 2016 to predict Trump’s victory and Republican success in the Senate, the latest whiffs are a black eye to the industry.
“The biggest problem in 2016 and 2020 was not that the polls were far off; it’s that they were all off in same direction,” said Andrew Smith, director of the University of New Hampshire Survey Center.
“If the problem were a random error, it would have gone both ways,” he said. “Some mistakes would favor Democrats and some would favor Republicans.” But that didn’t happen.
So what’s causing the systemic distortion? Polling experts say there’s a simple two-word answer: Donald Trump.
In the 2018 midterms, when Trump’s name wasn’t on the ballot, the polls if anything were more accurate than usual, said Terry Madonna, director of the Franklin & Marshall College Poll. It’s only when Trump is running that the polls fail to pick up Republican strength.
There has been a lot of speculation as to why this is, ranging from “shy” Trump voters who are reluctant to admit their preferences to deliberate media bias.
Pollsters have other explanations. And interestingly, they say the problem in 2020 was different from the problem in 2016.
The polling industry conducted extensive postmortems to figure out what went wrong in 2016, Madonna said. Franklin & Marshall “conducted exit polls of people we polled earlier to see what happened.”
Two things happened. One of them was that undecided voters in 2016 broke extremely heavily for Trump in the last days of the election, after FBI Director James Comey reopened his investigation of Hillary Clinton’s emails.
But there were few public surveys in the critical battleground states in the week before the election and thus no one picked up on the shift.
Franklin & Marshall’s postmortem revealed that “a huge percentage of people made up their minds or changed their minds in part due to Comey,” Madonna said.
The other problem was that people without a college degree voted in unusually large numbers and voted heavily in favor of Trump.