Are Clinton and Trump Really in a Dead Heat?
Policy + Politics

Are Clinton and Trump Really in a Dead Heat?

Donald Trump was crowing this morning.

He tweeted: “New Q poll out- we are going to win the whole deal- and MAKE AMERICA GREAT AGAIN!”

Trump bragging on Twitter is definitely in the “not news” category, but in this case he had reason to strut in 140 characters.

A new poll by the Quinnipiac University Polling Institute shows presumptive GOP presidential nominee Trump in a statistical dead heat with presumptive Democratic nominee Hillary Clinton.

The poll shows Clinton at 42 percent vs. Trump at 40 percent.

Related: Clinton and Trump Tied in 2016 ‘Bad Choice’ Election

You might think that being two points behind your rival -- or neck and neck, given the poll’s 2.4-point margin of error -- isn’t that impressive. But the Quinnipiac poll flies in the face of other recent surveys that show Clinton with double-digit leads.

Just last Sunday, a story about a new Washington Post-ABC News poll said support for Trump had plunged and cited results that showed Clinton at 51 percent and Trump at 39 percent, with a plus or minus margin of error of 4 percent.

And while other slightly earlier polls did not give Clinton as big a lead, they supported the Washington Post-ABC News storyline that voters are turning off on Trump. A Reuters/Ipsos poll conducted from June 18-22 had Clinton ahead by 10 points; and a Rasmussen Reports poll from June 20-21 and an NBC/Wall Street Journal poll from June 19-23 both gave her a 5-point lead.

So, is Quinnipiac an outlier?

Related: Here’s Why Clinton Will Lose the Election to Donald Trump

In the New York GOP primary on April 19, the Real Clear Politics average of all polls taken gave Trump a 30.3 percent margin of victory. The Quinnipiac Poll had him ahead by 35 points. He won by 35.3.

But Quinnipiac hasn’t always been on the money in this election cycle. It had Trump ahead by 15 points in the New Jersey GOP primary. He won with 80.4 percent of the vote, 67 points ahead of second-place John Kasich. Quinnipiac saw a tie between Trump and Kasich in Ohio. Kasich won his home state by 11.1 points. In Florida, Quinnipiac gave Trump a 24-point edge; he won by 18.8 points.

And in the first contest of the year, the Iowa Caucuses on Feb 1, Quinnipiac -- like every other poll, including the Des Moines Register/Bloomberg survey -- was wrong. All predicted a Trump win. Instead, Texas Senator Ted Cruz was the victor.

However, among eight Iowa polls of Democrats, Quinnipiac was only one of two that predicted a win for Senator Bernie Sanders. He lost by 0.2 points, but that defeat was surprisingly narrow and proved a harbinger of how much stronger-than-expected a challenger to Clinton he would be.

Related: Veteran GOP Pollster Predicts Clinton Over Trump in November

In 14 Republican primaries, the polls underestimated the size of Trump victories, sometimes by just a point or two but sometimes, especially in the large states, by double digits. In the New Jersey primary that Trump won by 67 points, the highest predicted margin of victory was 55. In California, where he won by 64.1, the most optimistic poll had him also ahead by 55 points.

Still, Charlie Cook of the highly regarded Cook Political Report, said that poll averages are a more reliable measure. “In a race with a lot of surveys, when a poll is very different from the averages, you should always regard it with some degree of skepticism,” he said. The Real Clear Politics average has Clinton ahead by 6.2 points today.