The Bradley Effect, Revisited

I doubt that I get as many e-mails on any single subject as I do on the Bradley Effect. In a feature for Newsweek, I take one last more look at the phenomenon:
There is little doubt Obama is losing some votes due to his race; a recent Associated Press survey suggested that as many as 6 percent of the electorate may be voting against Obama because he is black. But that's not what the Bradley effect is about. As long as those prejudiced voters are telling pollsters that they're going to vote for McCain, their sentiments will be reflected accurately in the polling. The Bradley effect emerges when voters tell pollsters one thing and then do another at the ballot booth.

So the question is why, if a voter does not intend to vote for Obama, would he or she feel compelled to lie about it? There are perfectly legitimate reasons not to vote for Obama; a voter who wanted to vote against him because of his race would have little trouble rationalizing his vote. If a voter felt compelled to lie to a pollster, he might tell them that he was voting against Obama because of his inexperience or his liberal politics—when, in fact, he was voting against him because of his race. But the pollster would still tally the vote correctly in the McCain column. By contrast, in cases where the Bradley effect existed, including Bradley's race itself, the black candidate was as much or more experienced than the white opponent. So voters found it harder to excuse their racism and may have misstated their voting intention to pollsters as a result.
My conclusion?
With so many "X factors" like race, cell phones and turnout, there is probably an extra margin of error this year. And polls aren't terrifically accurate to begin with. But there is no reason to conclude that the polls are systematically overestimating Obama's support; the reverse is at least as likely to be true. McCain, in all likelihood, will need to win this election fair and square—which means that he has his work cut out for him.

-- Nate Silver at 8:45 AM Electoral Projections Done Right: The Bradley Effect, Revisited