The new poll from Reuters/Ipsos comes as both candidates are strongly encouraging their supporters to cast ballots early. The president has made a particularly aggressive push for supporters to vote early in crucial swing states including Ohio. Early voting has already begun in 40 states.

But the 28-point advantage for the president could be the result of some less-than-ideal polling methods.


The Reuters poll was conducted online; pollsters have found that surveys conducted over the phone are more accurate. And while the overall Reuters poll surveyed 6,704 individuals, only 361 said they had voted early.

That gave the early-voting survey a plus-or-minus 10 percentage-point margin of error — a difference that the president still handily exceeded, but one much larger than usual for a presidential poll.

In a memo Monday from Romney political director Rich Beeson, the Republican campaign noted that the poll represented a survey of fewer than a dozen people in most swing states, and emphasized the small sample size involved.

"To claim a 'big advantage' based off of a phase that’s just 6 percent complete is almost as absurd as predicting the outcome of a baseball game after the second out," wrote Beeson.

Beeson said that even if the president did post an advantage, it simply reflected differing priorities from the campaigns.

"Democratic ballots are from high-propensity voters who would almost certainly be voting on Election Day — meaning that President Obama is cannibalizing his turnout on Nov. 6," said Beeson. "Gov. Romney’s early-voting effort has been, and will continue to be, focused on low-propensity voters, which means his Election Day turnout will not be negatively impacted by the early-vote program."

Meanwhile, the Obama campaign said Friday — before the release of the poll — that in Iowa and Ohio, registered Democrats have requested and cast more early ballots than have Republicans, and by a larger margin than in 2008. In Florida, Democrats have cut into the Republican lead in absentee requests from 2008, better than halving that advantage. And in Nevada, Democrats have outpaced Republicans in absentee ballot requests — a reversal from the last election.

"We have been in these communities for a long time, and we've been more prepared to get out the vote," Obama national field director Jeremy Bird said on a conference call Friday.

This post was updated at 9:17 a.m.