Polls differ on US election leader

Two recent national polls showed one of the presidential candidates moving ahead of the other.

They just couldn't agree on which one.

A Pew Research Centre survey of likely voters conducted from Thursday to Sunday gave Republican nominee Mitt Romney a four-percentage point lead over President Barack Obama. A Gallup poll of registered voters held from October 1 to Sunday showed Obama advancing over Romney by five points. In a shorter tracking survey of three days immediately following their October 3 debate, it called the race a tie.

The conflicting results underscore the lack of clarity in an environment in which, almost every day, new polls are released that vary depending on how voters are contacted, how they are counted and other variables tied to an individual polling group's approach to conducting surveys.

Both Democratic and Republican pollsters have a general sense Romney's support has grown and Obama's slipped since the former Massachusetts governor's performance in last week's first presidential debate in Denver. There's little consensus, though, on how deep or enduring that change in the race's dynamic may be.

"Romney clearly has gotten a boost coming out of the debate and it's for obvious reasons," said Whit Ayres, a Republican pollster who has worked on several presidential and congressional campaigns and is part of National Public Radio's bipartisan polling team.

Even so, Ayres said he was looking for more of a pattern that showed Romney closing a gap with Obama before pronouncing the gains were lasting ones.

Peter Hart, a long-time Democratic pollster who has run surveys for The Wall Street Journal and NBC News, agreed. "Romney has been helped" by his debate performance. Yet "a pattern is a series of results showing something in the same direction," he said. "It's just too few polls and too few days."

The Pew poll showed Romney backed by 49 per cent of likely voters and Obama with the support of 45 percent. The Gallup survey of registered voters showed Obama was the choice of 50 per cent and Romney was backed by 45 per cent.

Additional reporting by Agence France-Presse and The New York Times