A new poll puts Trump ahead of Clinton - but what does it all mean?

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A new opinion poll suggests that Donald Trump is just edging ahead of Hillary Clinton in the race to become America's next commander-in-chief.

According to ABC news, Trump is on 46% of the vote while Clinton is on 45%.

With just six days to go until the election on November 8, it's worthwhile taking a look at the importance of polls to better understand what this might all mean.

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Q. Should we take this poll seriously?

Hillary Clinton
(Patrick Farrell/AP)

A: As with all opinion polls, it is a snapshot, not a prediction. The small sample size means there is a margin of error of 5.5 percentage points.

It's also at odds with other polls conducted recently, which show Clinton with a small but steady lead.

Q. How reliable are polls this close to the election?

Barack Obama
(John Minchillo/AP)

A: Recent history suggests they should be treated with caution. In 2012, they showed Republican candidate Mitt Romney roughly neck-and-neck with US president Barack Obama right up to election day. Obama went on to win 51% of votes to Romney's 47%.

Q. So the polls are best ignored?

Barack Obama
(John Minchillo/AP)

A: They are not entirely worthless - they are a snapshot of the public mood and, if a trend begins to emerge, can point to a shift in opinion. But this is a nationwide poll and therefore has only limited value.

Q. What's the problem with national polls?

Capitol Hill
(Susan Walsh/AP)

A. The US presidential election is not strictly a national election. The winner is not whoever gets the most votes in the entire country. Instead the winner will be decided on the basis of who gets the most votes in each of the 50 states. As such, the polls in individual states are more useful when trying to forecast the outcome.

Q. What do the latest polls in the states show?

Hillary Clinton
(Andrew Harnik/AP)

A. They suggest that Hillary Clinton currently has a small lead where it matters: in the so-called swing states, such as Colorado, North Carolina and Florida. These are states which tend to shift their allegiance between the Democrats and Republicans.

Around a dozen of the 50 states can be classed as swing states. The rest are "safe" for either the Democrats (such as California and New York) or the Republicans (Louisiana and Tennessee).

Q. So some states are more important than others?

Donald Trump
(Evan Vucci/AP)

A. Yes. Each state is worth a number of votes in what is called the electoral college. This number is based on population size - so California, a very populous state, is worth 55 votes while the sparsely-inhabited Montana is worth just three.

A candidate collects all the electoral votes for a state by coming top of the popular vote. For example, in Florida the polls suggest Clinton currently leads Trump by 46% to 44%. If this were repeated on election day, Clinton would collect all of Florida's 29 electoral college votes.

Q. Who needs to win more of these swing states?

Donald Trump
(Evan Vucci/AP)

A. Trump. There are fewer Republican safe states, so Trump needs more of the swing states to get a majority of the electoral college (270 votes out of 538). He has around 160 votes from safe states, while Clinton has around 250.

Q. Has a candidate ever won the popular vote nationwide but still lost the election?

Al Gore
(Mike Stocker/AP)

A. Yes: this is what happened in 2000, when the Democrats' Al Gore won 51.0 million votes and the Republican George W Bush won 50.5 million. But Bush won more votes in the electoral college (271 to Gore's 266) and ended up president.