Accuracy Of Polls a Question In Itself

"As other public polls begin to show Senator Obama dropping below 50% and the margin over McCain beginning to approach margin of error with a week left, all signs say we are headed to an election that may easily be too close to call by next Tuesday," McCain pollster Bill McInturff wrote in a memo released last night by the campaign. Obama officials voiced confidence in their ultimate victory but said they have always expected the election to be close.

To buttress its point of view, the McCain team points to results reported yesterday by the Gallup organization, whose daily tracking poll showed Obama up 49 percent to 47 percent using Gallup's traditional turnout model, which assumes that turnout will follow the patterns of past elections. Obama has a larger lead, seven points, using a model that allows a higher presence of first-time voters.

A Pew Research Center poll released yesterday shows a 15-point lead for Obama, a result based on relaxed criteria for when to consider an African American respondent a likely voter, said Andrew Kohut, president of the center. He said the poll shows that roughly 12 percent of the electorate this year is black, up from 2004, with a similar increase among younger voters. Kohut defended this approach, saying there are historically high levels of interest in this contest among both demographic groups. At the same time, he added, "we've consistently shown less enthusiasm and engagement among Republicans than is typical, and the composition of the electorate shows that."

Kohut said several variables signal Obama has not convinced voters, such as a large number of respondents in the Pew poll who see the Illinois Democrat as a risky choice. But Kohut said the odds are against "a huge shift" in voter preferences by Election Day.

Some polls show Obama with a healthy lead even without an assumed surge in African American and young voters. Obama's seven-point lead in the Washington Post-ABC News poll is not premised on disproportionately higher turnout among those demographic groups. The poll's turnout model currently shows that 10 percent of likely voters are black, compared with the 11 percent who voted in 2004, according to the network exit poll. Voters younger than 30 make up 16 percent of the Post-ABC sample, little different from the 17 percent four years ago.

Post polling director Jon Cohen said the survey designers "carefully consider a range of likely voter scenarios and use our best judgment. Our polling throughout the campaign has been on target and, we believe, helpful to understanding what is really happening. I hope it stays that way."

He noted that to address "one potential pitfall," The Post and ABC conduct interviews with a random selection of those who have only cellular phone service alongside a traditional random sample of those with residential phone service. One recent criticism of current polling has been that it does not accurately capture the sentiments of those who primarily use cellphones.