Bradley Effect, or *Reverse* Bradley Effect?

Three weeks to Election Day and polls project a victory, possibly a big one, for Barack Obama.

Yet everywhere, anxious Democrats wring their hands. They’ve seen this Lucy-and-the-football routine before, and they’re just waiting for their ball to be snatched away, the foiled Charlie Browns again. Remember how the exit polls in 2004 predicted President Kerry?

The anxiety is more acute this year, because Senator Obama is the first African-American major-party presidential nominee. And even pollsters say they can’t be sure how accurately polls capture people’s feelings about race, or how forthcoming Americans are in talking about a black candidate.

In recent days, nervous Obama supporters have traded worry about a survey — widely disputed by pollsters yet voraciously consumed by the politically obsessed — that concluded racial bias would cost Mr. Obama six percentage points in the final outcome. He is, of course, about six points ahead in current polls. See? He's going to lose.

If he does, it wouldn't be the first time that polls have overstated support for an African-American candidate. Since 1982, people have talked about the Bradley effect, where even last-minute polls predict a wide margin of victory, yet the black candidate goes on to lose, or win in a squeaker. (In the case that lent the phenomenon its name, Tom Bradley, the mayor of Los Angeles, lost his race for governor, the assumption being that voters lied to pollsters about their support for an African-American.)

But pollsters and political scientists say concern about a Bradley effect — some call it a Wilder effect or a Dinkins effect, and plenty call it a theory in search of data — is misplaced. It obscures what they argue is the more important point: there are plenty of ways that race complicates polling. Considered alone or in combination, these factors could produce an unforeseen Obama landslide with surprise victories in the South, a stunningly large Obama loss, or a recount-thin margin. In a year that has already turned expectations upside down, it is hard to completely reassure the fretters.

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In this year’s Democratic primaries, University of Washington researchers found a Bradley effect in three states, but a reverse Bradley effect in 12 (in the other 17, polls were within a seven-point margin of error).

The results tended to correlate with the black population in a state: blacks made up 15 percent or more of the population in almost all the states where the polls showed less support for Mr. Obama than there actually was; in the three states where polls showed more support than there was, less than 10 percent of the population is black.

The differences are too great to be explained by just high black turnout, said Anthony Greenwald, one of the researchers. Nor were people necessarily lying. Instead, he sees a cultural dynamic at work: the states where polls underpredicted support for Mr. Obama were generally in the Southeast, where the culture has more stubbornly favored whites, so the "right" answer there was to choose the white candidate. In the three states where polls in the study overpredicted support for Mr. Obama — Rhode Island, California and New Hampshire — "the desirable thing is to appear unbiased and unprejudiced," Mr. Greenwald said. (Many polling experts also believe that Mr. Obama was benefiting from an Iowa bounce in the late New Hampshire polls, as Senator Hillary Rodham Clinton had been ahead for months, and that therefore Mr. Obama’s loss there was not a true Bradley effect.)