A casual observer of national polling on the White House race might conclude that Hillary Clinton is the assured victor.

All but four of the surveys taken since the first general election debate that are included on industry website Real Clear Politics have Clinton winning head-to-head match-ups against Donald Trump. She leads him by an average of 5.5 percent in recent surveys.

When Libertarian Gary Johnson and Green Party candidate Jill Stein are options, Clinton is still ahead by 6.3 percent.

However, Helmut Norpoth, a political science professor at Stony Brook University and an election forecaster whose model has correctly predicted the last five national contests, is advising voters to 'hold off on trusting poll-driven proclamations of a Clinton victory just yet.'

'Clinton leads, but our polling methods are bunk,' the headline of his latest op-ed for The Hill declares.

A casual observer of national polling on the White House race might conclude that Hillary Clinton is assured victory

Clinton leads Donald Trump by an average of 5.5 percent in recent surveys

All but four since the first general election debate included in industry website Real Clear Politics' calculations have Clinton ahead. Norpoth says they're 'bunk'

Professer Helmut Norpoth's model, which has been correct since it was first used in 1996, has Donald Trump winning the election with an 87 percent degree of certainty

Norpoth's model, which has been correct since it was first used in 1996, has Donald Trump winning on Nov. 8 with an 87 percent degree of certainty.

Based on Trump's and Clinton's performances in their party primaries, The Primary Model projects that the Republican businessman will beat the former secretary of state with 52.5% to her 47.5% of the two-party vote.

His assertion flies in the face of FiveThirtyEight's election forecast, which is rooted in polling and says there's an 86.6 percent likelihood that Clinton will win. Trump has a 13.4 percent chance of pulling it off on the Nate Silver-helmed site.

Helmut Norpoth, a political science professor at Stony Brook University and an election forecaster, has correctly predicted the last five national contests

When other factors are considered like the economy and historical data Clinton still has an 83.1 percent shot at the presidency on FiveThirtyEight. Trump 18.9 percent chance.

The Huffington Post's poll tracker includes 177 surveys from 35 pollsters. It says it's 'very likely' that Clinton is leading because she comes out ahead of Trump 99 percent of the time.

'To start with something basic, opinion polls are really about “opinions,” not actions. At their best, they can tell us how people feel about political issues and personalities,' Norpoth explains.

Just over a majority of Americans show up to vote, he points out, nearly six in 10. Those are the 'likely voters' referred to in polls.

'They are the only ones that count. But to find them is no easy chore,' Norpoth states. 'It is ingrained in all of us that voting is civic duty. So nearly all of us say, oh yes, I’ll vote, and then many will not follow through.'

That leads to miscalculations, he writes.

Norpoth points out that the pollsters have called it for the wrong candidate on several previous occasions such as 1948, when Tom Dewey was consistently ahead.

Pollsters ceased their activity, assuming Dewey would win, and he was bested on Election Day by Harry Truman.

Norpoth's model has been correct since it was first used in 1996. Based on Trump's and Clinton's performances in their party primaries, The Primary Model projects that the Republican businessman will beat the former secretary of state with 52.5% to her 47.5% of the two-party vote

Gallup in 2012 projected that Mitt Romney would be the next president. Barack Obama came out ahead of him by four points. This cycle the esteemed polling organization isn't trying to predict the outcome of the presidential election at all.

Rasmussen also got it wrong in 2012. It's also one of the only major outfits that has had Trump outpacing Clinton since their Sept. 26 cage fight Hofstra University.

One other, Gravis, has them tied. The LA Times daily tracking poll, which surveys the same sample of voters over and over again, gives Trump a one-point lead.

A just-released Rasmussen poll has Clinton up by two, though.

A Politico/Morning Consult poll that came out this morning that isn't reflected in the Real Clear Politics data has Clinton with a six-point advantage over Trump - 42-36.

Johnson gets 10 percent of the vote in that poll and the Green Party's Jill Stein has three.

Clinton told her supporters last week during a Miami radio interview that she doesn't believe she's as far ahead as the surveys say, and they shouldn't either.

'I don't trust the polls. They've been all over the place in this campaign,' she said. 'I don't believe them when they're up. I don't believe them when they're down. I just try to work hard every single day.'

Clinton was responding to an NBC survey that put her 11 points in front of Trump - her largest lead since early August.