The Biden campaign appeared to place big bets late in the campaign in the hopes that the public polling would be right, expanding its television buy to states Trump would win easily. In the final week, Biden made appearances in Ohio, where he stands eight points behind with 93 percent of votes counted, and Iowa, where he lost by eight points with 92 percent of votes counted.

“We were operating in a reality that wasn’t reality, and we were operating off numbers that just were clearly not reflecting what turnout would be,” said one Democratic consultant, who spoke on the condition of anonymity to speak frankly. The Biden campaign officials have maintained that their internal polling proved more accurate than the public numbers.

Although the degree of polling misses is not yet clear as states continue to count mail-in ballots, a review of polling in 10 key states with more than 85 percent of the vote counted finds that public polls underestimated Trump’s vote margin by about 4.5 percentage points on average, similar to the size of errors in key states four years ago.

Polling problems were again concentrated in the Upper Midwest, with averages of polls in Wisconsin and Michigan showing Biden with leads of seven to eight percentage points before Biden eked out one- and three-point victories, respectively. Pennsylvania remains a close race, though Biden is likely to fall short of his five-point advantage in pre-election polls.