Why Quinnipiac's polls look so much better for Donald Trump than everyone else's

On Wednesday, Quinnipiac University published a string of polls with terrible news for Hillary Clinton.

Though Clinton leads in most national polls, Quinnipiac put Donald Trump ahead of her by a few points in Florida and Pennsylvania and even with her in Ohio. The polls also showed Trump’s lead widening to 5 points in Florida and 6 in Pennsylvania when libertarian candidate Gary Johnson was included.

If those numbers held up, Clinton would probably lose the general election, and Trump would become the president of the United States. So whether those polls are accurate is no small matter.

But before you start preparing to move to Canada, you should know that Clinton is probably, based on national polling averages, still leading the race. Moreover, most other pollsters have continued to find Clinton running ahead of Trump in most battleground states. So why do Quinnipiac’s numbers suggest a different outcome?

Quinnipiac’s polls show white voters accounting for a much bigger share of the vote than was the case in 2012

There’s no way of knowing whether Quinnipiac polls are accurate until Election Day actually arrives. But skeptics looking closely at Quinnipiac’s results have found things to quibble with.

As the University of Virginia’s Kyle Kondik pointed out on Twitter, Quinnipiac is finding a pretty massive swing from just a few weeks ago in these battleground states — a swing that’s much bigger than the movement we’ve seen in national polling.

Other skeptics raised more specific objections. Most prominently, the polls show white voters representing a significantly greater proportion of the electorate than they did in 2012, even though the electorate is growing more diverse.

In the new Quinnipiac polls, white voters accounted for about 83 percent of voters in both Ohio and Pennsylvania. But as some have pointed out, whites only accounted for about 76 percent of the 2012 vote share in both of those states.

Now, it’s of course possible that Trump will cause turnout to surge among white voters in November. As Josh Marshall notes at Talking Points Memo, expecting a larger share of white voters doesn’t necessarily amount to a "bias" on Quinnipiac’s part — it’s more likely that the firm is just seeing a more GOP-friendly electorate than other pollsters.

In a Facebook post, Quinnipiac defended its projections, arguing that assuming the 2016 electorate would look like 2012’s amounted to "guess work, not scientific polling." But for Quinnipiac’s numbers to hold, you’d probably have to assume Trump doesn’t spur a massive increase in turnout among Latino voters for Clinton. And that’s a debatable premise, to say the least.

Focus on the national poll aggregators instead

In any case, state battleground polls aren’t necessarily the best way to understand the state of the race right now. State-by-state polling tends to be very volatile because it relies on smaller sample sizes says Julia Clark, senior vice president at Ipsos Public Affairs. Pollsters also tend to have more difficultly modeling turnout for individual states.

Instead, anyone trying to understand the state of the race should probably look to the national polling numbers. More specifically, experts try to look at the so-called "polling aggregators" that average the findings of all the major pollsters.

National polling isn’t all good news for Hillary Clinton, notes Jeff Cartwright, director of communications at Morning Consult. A New York Times poll released Thursday put Clinton and Trump deadlocked, and NBC News, the Economist/YouGov, and McClatchy/Marist have all found Clinton’s lead shrinking.

So it’s possible that Quinnipiac’s poll is detecting an early wave of voters shifting to Trump, says Pat Smith, a spokesperson for Quinnipiac: "Right now, people are upset about the Orlando and Dallas attacks; historically, there’s a trend toward the candidate perceived as being more law and order."

Still, for now, at least, Clinton does appear to be retaining a fairly commanding lead among the polling aggregators. RealClearPolitics has consistently found Clinton up by around 5 points:

Similarly, there’s the Huffington Post’s polling average, which has Clinton up by 5 points overall:

Of course, none of this means Clinton’s lead is sure to hold. The Clinton campaign, for one, doesn’t want anyone growing complacent.

"We know the battlegrounds are going to be close till the end. That's why we need to keep working so hard," Clinton press secretary Brian Fallon tweeted Wednesday morning. "Trump is a serious danger, folks."

The bad map we see every presidential election

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