Persistent Errors by Pollsters Favored Democrats in the 2020 Election

Pollsters consistently overestimated the share of votes for President-Elect Joe Biden and Democratic Senatorial candidates in the 2020 election.  While polls correctly predicted Biden’s victory, polling averages overestimated his margins in states he won and underestimated Donald Trump’s margins in states that Trump won. The errors were not the result of random variations in sampling.  […]