A little over a fortnight away from the US presidential election, Democratic hopeful Joe Biden is ahead of President Donald Trump in various opinion polls, AFP reported. The former vice president is ahead of his Republican challenger by 9.0 percentage points nationally, according to polling averages from the RealClearPolitics website.

Even Trafalgar Group, a polling institute favored by Republicans, is giving advantage to Biden in crucial states such as Pennsylvania and Wisconsin, AFP reported.

But, Trump’s victory in the 2016 election has brought into question the reliability of opinion polls. Also, in the US, candidates win the White House not through the popular vote, but with the Electoral College.

In 2016, Trump lost the popular vote to Hillary Clinton but won enough states to garner the electoral votes needed to become president.

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This year, six states are seen as key to winning the White House: Florida, North Carolina, Arizona, Wisconsin, Pennsylvania and Michigan.

But if the polls are correct, Biden also has the advantage there, although he is at times within the margin of error, ranging from 1.7 percentage points ahead in Florida to 7.2 in Michigan.

The polls on the eve of the vote correctly predicted a slight national lead for Clinton, but “the place where the polls missed were in some of those Midwestern swing states” that Trump eventually won, Chris Jackson of Ipsos Public Affairs told AFP.

He said under-representation within polling samples of white residents without college degrees who voted for Trump was among the causes.

According to an AFP report, most polling institutes have said they’ve corrected their methodology to preclude such mistakes this time around. Battleground states under-polled last time have been surveyed much more closely and more often.

Also, Biden has been ahead of Trump with an average lead which has never fallen below four percentage points. As a comparison, the Trump-Clinton polling lines crossed twice, signaling an uncertain race.

The country is a lot more polarised than it was in 2016, thus there are far fewer undecided voters susceptible to altering the contest at the last minute. Also, four years ago, the businessman and political newcomer was a novelty, and such candidates are always difficult for pollsters to assess.

Meanwhile, Trump has hit out at these polls. “The polls were wrong last time, and they’re more wrong this time,” he has said.

The New York Times has calculated that, even if the current polls, state by state, are as wrong as they were four years ago, Biden would still win.

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“Mr. Biden is closer in our poll average to winning Texas, which would get him over 400 electoral votes than President Trump is to winning in traditional battleground states like Pennsylvania and Nevada,” the paper’s Nate Cohn wrote recently.

Pollsters and analysts are still careful to note that voters’ intentions are not a prediction and that there is still a margin of error.

With 16 days to go in 2016, the FiveThirtyEight site gave Clinton an 86% chance for victory, nearly the same as Biden now, AFP reported.

In the United States, voter registration varies enormously, which makes it especially difficult to predict turnout.

Meanwhile, Trump has pointed to enthusiastic crowds at his rallies to argue that momentum is on his side. 

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But, the COVID-19 pandemic has played its role. With the US recording the highest number of cases and fatalities, voters tend to be disenchanted with the President.