Americans will vote on 8 November to choose their next president.
How important are national polls?
It’s a tough task to gauge the mood of a nation that is home to more than 300 million people but that doesn’t stop the pollsters from trying.
National polls tend to have a sample size of about 1,000 people or more and can track movement and general opinion pretty well.
But the US election is won and lost in swing states and decided by the electoral college system.
This means that polls in states that look like they could vote for either candidate (Florida, Ohio and Pennsylvania, to name just a few) play an integral role in election projections.Who is ahead in the battleground states?
We’ve identified 13 states that can be considered battlegrounds in this election.
The map below shows them and which way they’re likely to vote based on data collected by polling resource website Real Clear Politics.
If those states stay the same colour (blue for Clinton, red for Trump) through to election day – and both candidates win the remaining states they are expected to – it would be a clear victory for Hillary Clinton.
For Donald Trump to have a chance, he needs to turn Florida and Ohio red and win a few others too. As it stands, while Trump is just edging Ohio, but Clinton is leading in Florida.
The latest poll averages in the battleground states are shown in the chart below. Some states are polled more frequently than others; not all the polls below will be showing a result from the same survey period.
How have scandals affected Trump’s poll numbers?
Donald Trump has been hit by several scandals since his campaign began. The most notable was the release on 7 October of a video in which he can be heard boasting about sexually assaulting women. He said his comments were “just words” and denied ever having groped a woman – but several have since come forward alleging just that.
This would have been enough to end the campaigns (and political lives) of many candidates, but Mr Trump has survived. Indeed, one CNN poll released on 24 October put him on 45% – exactly the same figure he was on in the previous CNN poll released on 3 October. Both polls had Mrs Clinton leading on 51%.
Mr Trump’s ability to continuously poll around 40% nationally while rarely going above 45% has led many analysts to describe his support as having a high floor but a low ceiling. Mr Trump got more primary votes than any Republican in history but the polls show he has struggled to attract voters from outside his large and loyal base.
Are Trump and Clinton the only candidates?
No. They’re the only candidates that stand a real chance of winning the race but there are also third-party and independent candidates in the running.
The rules around getting on the ballot differ from state to state but most voters will have two main alternatives to Hillary Clinton and Donald Trump.
Green Party candidate Jill Stein, 66, is a doctor and activist who is hoping to pick up Democrats who backed Bernie Sanders and continue to rally against Mrs Clinton.
Former New Mexico governor Gary Johnson, 63, is standing for the Libertarian Party and focusing his efforts on attracting Republicans uneasy with Mr Trump.
According to Real Clear Politics, Mrs Stein is still picking up about 2% of the vote in a four-way race while Mr Johnson’s numbers have dropped slightly since September to about 6%. Neither can win the race with stats like that, but they could siphon enough voters off the major candidates to change the outcome in a close race.
How did the VP picks affect the polls?
In the past, an astute pick for a candidate’s running mate could earn them a double-digit boost in the polls – Bill Clinton got a 12-point bounce after naming Al Gore as his pick for vice-president in 1992.
But in recent years the bounces have been far smaller, and 2016 followed that trend.
Neither Trump’s choice of Indiana Governor Mike Pence (15 July), or Clinton’s unveiling of ex-Virginian governor Tim Kaine (22 July) changed much in the polls.
BBC