Election Update: The Blue State Polling Abyss

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Public Policy Polling on Wednesday released a poll of New Mexico, a state that hasn’t attracted much attention. Hillary Clinton led Donald Trump by 9 percentage points, while the Libertarian candidate and former New Mexico Gov. Gary Johnson had 16 percent of the vote.

The margin was a little closer than you might expect given Clinton’s 6 or 7 percentage point national lead and New Mexico’s demographics. But we don’t know very much about how New Mexico and a lot of other states like it are voting this year. The PPP survey was the first poll of New Mexico since PPP’s previous poll of the state in May. Other blue-leaning states have also received scant polling: Minnesota has barely been polled, for instance, and Maine hasn’t been polled much given that at least one of its electoral votes could be highly competitive.1

“Who cares?” you might protest. A 9 percentage point margin isn’t exactly close. Pollsters seem to think it’s more fun to poll traditionally red states such as South Carolina and Missouri — and, in fact, those states have been tight in recent surveys.

But while South Carolina and Missouri could allow Clinton to run up the score in the Electoral College, they’re very unlikely to determine the winner. In any election in which she wins South Carolina, for example, Clinton will almost certainly have already won North Carolina and probably also Georgia, meaning that she’ll be on track for 300-plus electoral votes with or without the Palmetto State. South Carolina and Missouri are unlikely to be tipping-point states, in FiveThirtyEight parlance.

By contrast, states such as New Mexico, Minnesota and Maine potentially could be tipping-point states if Trump makes a comeback. The polling there — showing Clinton leads in the high single digits or low double digits — isn’t far removed from the numbers in the more glamorous battleground states, such as Colorado, Virginia, Wisconsin and Pennsylvania, which have received far more attention.

And although they aren’t remotely competitive, the polling in populous blue states such as New York and California is also more important than you might think. These states have a lot of votes, making them important for understanding the relationship between the popular vote and the Electoral College. Recently, Clinton’s numbers have seemed to be a bit stronger in state polls than in national polls. Could that reflect her advantages in battleground states, such as her greater advertising presence and her better field operation?

Well, perhaps. But it’s not just battleground states where Clinton’s gotten good numbers; she’s also considerably overperforming Barack Obama in red states. Blue states are the missing part of the puzzle. Could it be that Clinton is underperforming in those? In the table below, you’ll find a comparison of Obama’s margin of victory in 2012 against Clinton’s current adjusted polling average in each blue state where we have at least one poll. By blue state, I mean everything Obama won by a wider margin than he did Wisconsin in 2012 (7 percentage points).

STATEOBAMA MARGIN OF VICTORY, 2012CLINTON LEAD IN ADJUSTED POLLING AVERAGE, 2016Minnesota+7.7+9.3Michigan+9.5+8.4New Mexico+10.1+9.4Oregon+12.1+9.3Washington+14.8+15.8Maine+15.3+8.0Illinois+16.8+21.4Connecticut+17.3+10.5New Jersey+17.7+13.7Delaware+18.6+14.7California+23.1+25.0Massachusetts+23.1+24.9Maryland+26.1+30.6New York+28.2+20.4Vermont+35.6+21.9How big are Clinton’s leads in blue states?

Adjusted polling average is per FiveThirtyEight polls-only model as of Aug. 25

This is a mixed bag of results. Clinton’s generally underperforming Obama in the Northeast, including in Maine, Connecticut, New York, New Jersey and Vermont. She’s running slightly ahead of him in California, however, and perhaps more surprisingly — given that it was Obama’s home state — well ahead of him in Illinois.2 Overall, weighted by each state’s 2012 turnout, she’s running about half a percentage point behind Obama in these states. So perhaps there’s something to the notion that Clinton’s underperformance in blue states can help explain some of the seeming differences between state and national polls.

But I wouldn’t take this too far. The relative lack of polling in these states means that the data is noisy. It doesn’t make a lot of sense that Clinton is outperforming Obama in Washington but underperforming him in Oregon, for instance, as polls suggest. In some cases, the polls don’t match the demographics of the states very well either. Our polls-only model “thinks” that Clinton should be ahead in New Mexico by about 14 points, for example, based on the patterns it’s seeing in other states, and not just by 9. It’s less skeptical of the polls in overwhelmingly white Maine and Minnesota, however. Minnesota’s worth keeping an eye on provided that — because somehow this has become a problem for him — Trump can get on the ballot there.

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