Election polling postmortem finds flaws in polls of Midwestern states that went for Trump

Remember the chaotic election last November? How could we forget! If you followed the polls and listened to pundits, you could be forgiven for expecting Hillary Clinton to win by a large margin. But that’s not what happened, and the outcome surprised even some established pollsters, prompting an investigation of the election polls, which six months later has now been completed.

The new report released today [I’ll include a link here] by the American Association for Public Opinion Research finds that, no, the polls aren’t “broken.” National polls fared pretty well, while Midwestern state polls missed a big segment of voters leaning toward Donald Trump. The letter from FBI director James Comey about the Clinton email probe appeared to cause a small temporary shift, and quite a few undecided voters broke for Trump at the last minute, but despite that Clinton won the national vote by 2.1%, almost as much as forecast (3%) and well within the uncertainties. But Trump’s victory in states like Wisconsin, Michigan, and Pennsylvania, where non-college educated suburban white people were politicized and turned out in large numbers, caught experts off guard. (Polls gave Clinton the edge in those three states, and had she won all of them, she would’ve won with 278 vs 260 electoral votes.)

The popular vote went for Clinton, but in the end, that doesn’t matter. Pollsters need to spend more time and effort on state polls, especially in “battleground” states, to improve those polls and more accurately get the voting preferences of all segments of the population of likely voters, including those who don’t respond as often to pollsters’ phone calls or online surveys. State polls throughout the upper Midwest seem to have missed non-college educated and working-class whites in suburban and rural areas, who turned out the vote more than expected and preferentially for Trump.

There’s a couple other findings worth noting, but I’d like to make a more important point about how polls are interpreted. Many people seem to have banked on Clinton’s narrow national lead, which did not translate into an Electoral College win. It wasn’t even close. “The horse race becomes interesting news fodder, but it’s misleading,” Michael Link, past president of AAPOR, tells me.

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