WASHINGTON (AP):

Barack Obama is galloping away with the presidential race. Or maybe he has a modest lead. Or maybe he and John McCain are neck and neck.

Results of recent major polls have been confusing.

In the past week, most surveys have shown Democrat Obama with a significant national lead over Republican McCain.

Focusing on 'likely voters' - as many polling organisations prefer this close to election day - an ABC News-Washington Post survey showed Obama leading by 11 percentage points. A Wall Street Journal-NBC News poll had the same margin, while the non-partisan Pew Research Center gave Obama a 14-point edge.

But others had the race much closer. CNN-Opinion Research detected an Obama lead of 5 points. The George Washington University Battleground Poll had Obama up by four points. And an Associated Press-GfK poll showed Obama at 44 per cent and McCain at 43 per cent - in effect, a tie.

Below are some questions and answers about why the polls differ.

A supporter of Republican presidential candidate John McCain raises a placard in reference to 'Joe the Plumber', who has become a centrepiece of McCain's election platform backing small businesses. - AP

Q: Don't pollsters simply ask questions, tally the answers and report them?

A: No. After finishing their interviews - usually with about 1,000 people, sometimes more - they adjust the answers to make sure they reflect Census Bureau data on the population like gender, age, education and race. For example, if the proportion of women interviewed is smaller than their actual share of the country's population, their answers are given more 'weight' to balance that out.

But some pollsters make these adjustments differently than others. And while most polling organisations, including the AP, do not modify the responses to reflect some recent tally of how many Democrats, Republicans and independents there are, some do.

Q: Are those the only changes made?

A: No. As election day nears, polling organisations like to narrow their samples to people who say they are registered voters. They often narrow them further to those they consider likely voters.

Q: What else might cause differences?

A: The groups pollsters randomly choose to interview are bound to differ from each other, and sometimes do significantly.

Every poll has a margin of sampling error, usually around three percentage points for 1,000 people. That means the results of a poll of 1,000 people should fall within three points of the results you would expect had the pollster instead interviewed the entire population of the US.

Democratic presidential candidate Senator Barack Obama, disembarks a plane to visit his ailing grandmother in Honolulu, Hawaii, Thursday night.

However, the results are expected to be that accurate only 95 per cent of the time. That means that one time in 20, pollsters expect to interview a group whose views are not that close to the overall population's views.

Q: Are the differences among polls this year that unusual?

A: Not wildly, but that doesn't make them less noticeable. There's a big difference between a race that's tied in the AP poll, and Pew's 14-point Obama lead. But because of each poll's margin of error, those differences may be a bit less - or more - than meet the eye.

That's because each poll's margin of sampling error should really be applied to the support for each candidate, not the gap between them.

Take the AP poll, which has a margin of error of plus or minus 3.5 percentage points. Obama's 44 per cent support is likely between 48 per cent and 40 per cent. McCain's 43 per cent is probably between 47 per cent and 39 per cent.

Q: Are people always willing to tell pollsters who they're supporting for president?

A: No, and that's another possible source of discrepancies. Some polling organisations gently prod people who initially say they're undecided for a presidential preference, others do it more vigorously. The AP's poll, for example, found nine per cent of likely voters were undecided, while the ABC-Post survey had two per cent.

WASHINGTON (AP):

Republican veep candidate Sarah Palin, on whom the Republican Party has lavished US$150,000 for designer clothes and beauty services, says her family shops frugally back home in Alaska and her favourite store is a consignment shop.

Purchases by the Republican National Committee at high-end department stores like Saks Fifth Avenue and Neiman Marcus appeared in spending reports filed with the Federal Election Commission. They offered a stark contrast to Palin's image as a "hockey mom".

FRANKLIN, Indiana (AP):

A Republican county clerk distributed to two employees an Internet blog posting referring to Democratic presidential candidate Barack Obama as a 'young, black Adolf Hitler'.

Johnson County Clerk Jill Jackson said Friday that she had apologised to the employees. One had complained to police.

The employees, who had voted for Obama in the Democratic primary, discovered the printouts at their desks after returning from holiday weekend in September.

NEW YORK (AP):

A Manhattan developer is trying to lure buyers to his new condominium tower with a sales gimmick - an 'Obama contingency clause' - aimed at Democrats.

Anyone who signs a purchase contract before election day on November 4 can back out, no questions asked, if Republican John McCain beats Barack Obama in the presidential race.

Developer Erik Ekstein says he's willing to put the 'Obama contingency clause' in any contract signed before November 4.