Long ago, I think when Barak Obama first ran for president as the first black candidate in 2008, on another internet forum I had a discussion with a political opposite (let's call him Jim) regarding polls in which he cited "the Bradley Effect."

Quick definition from WikipediaL The Bradley effect (less commonly the Wilder effect)] is a theory concerning observed discrepancies between voter opinion polls and election outcomes in some United States government elections where a white candidate and a non-white candidate run against each other.The theory proposes that some white voters who intend to vote for the white candidate would nonetheless tell pollsters that they are undecided or likely to vote for the non-white candidate. It was named after Los Angeles mayor Tom Bradley, an African-American who lost the 1982 California gubernatorial election to California attorney general George Deukmejian, a white person, despite Bradley being ahead in voter polls going into the elections.

As the election drew nearer, Jim insisted the Republican would win because though the polls had Obama ahead of McCain, Jim believed that people were lying to pollsters to hide the fact they didn't want to vote for black man. Well we know how that turned out.

But in the case of Bradley-the polling was EXIT polling. Exit polling had Bradley winning the election. Jim was asserting that the people leaving the polls lied to the pollsters. Did they? Turns out, in this case, the exit polling was entirely accurate. Bradley was winning among in-person voters. Where he lost was the elderly, presumably white, mail in voters who were not being polled on election day.