National surveys of the 2020 presidential contest were the least accurate in 40 years, while the state polls were the worst in at least two decades, according to the new, comprehensive report from the American Association for Public Opinion Research. But unlike 2016, when pollsters could pinpoint factors like the education divide as reasons they underestimated Donald Trump and offer specific recommendations to fix the problem, the authors of the new American Association for Public Opinion Research report couldn’t put their finger on the exact problem they face now. Instead, they've stuck to rejecting the idea that they made the same mistakes as before, while pointing to possible new reasons for inaccuracy... Decreasing response rates have been a major source of concern for pollsters for more than a decade. But the politicization of polling during the Trump era — including the feedback loop from the former president, who has falsely decried poll results he doesn’t like as “fake” or deliberately aimed at suppressing enthusiasm for answering polls among GOP voters — appears to be skewing the results, with some segment of Republicans refusing to participate in surveys. But pollsters say they can’t be sure that’s the main reason, because you never know exactly whom you’re not talking to.