Once again, polls underestimated Trump. Experts only have a hunch why

Contributing sentiments towards policy:

68% : With vote tallies nearly finalized, Trump led Harris nationally by 2 percentage points: 50% to 48%.
59% : (Reuters/Ipsos polling showed Harris leading Trump by 1 percentage point just ahead of the Nov. 5 election, in line with the 538 average of national polls.)
56% : Polls before the Nov. 5 vote had shown Trump trailing Democratic Vice President Kamala Harris by 1 percentage point, according to an average of dozens of national opinion polls compiled by 538, a website on data analysis for politics and sports.
48% : In the Rust Belt swing states of Pennsylvania, Wisconsin and Michigan - where Trump was behind in the surveys but won the vote - the polling averages similarly underestimated him by 2 to 3 points.
38% : Public opinion polls underestimated Trump support by 3 percentage points*Misses are marginal, but polls have underestimated Trump in three election cycles*Pollsters look to revise their approachBy Jason LangeWASHINGTON, Nov 20 (Reuters) -
37% : Public opinion polls did not similarly underestimate Republican strength heading into the 2018 and 2022 congressional midterm elections when Trump wasn't on the ballot, said Franklin.
29% : The American Association for Public Opinion Research postmortem following the 2020 election considered the possibility that polls underestimated Trump because his supporters responded less to surveys, consistent with his brand as a political outsider.
25% : TRUMP EFFECTPolling experts told Reuters they remain unsure of why polls underestimate Trump, who has railed against polls as biased against him throughout his political career.
17% : Polling experts and pollsters also say it is possible that pollsters are also introducing errors when they process their surveys' raw numbers to give more weight to the responses coming from people they consider most likely to actually vote.FINE-TUNINGMeasuring support for Trump seems to be a particular problem for pollsters.

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