Polls have faced strident criticism after President Trump outperformed pre-election surveys nationally and in key states. Now that nearly all votes have been counted, a clearer picture of poll accuracy has emerged, showing that they struggled much more in certain states, while they were much more accurate in others.

A review of polling in 10 key states finds that public surveys underestimated Trump’s vote margin against Joe Biden by about 3.6 percentage points from an average of final-week polls tracked by the website RealClearPolitics, similar to the size of errors in those states four years ago. That pattern was similar to national polls, which underestimated Trump’s vote margin against Biden by an average of 3.3 points, which is larger than the error in national polls four years ago.

The overall accuracy of what polls showed varied quite a bit across key states, with surveys sharply overestimating Trump’s standing in some while giving an accurate image of the race in others. Notably, some of the most difficult states to poll in 2016 proved to be challenging again in 2020.