Wednesday, November 9, 2016

A Few Thoughts on the Election and Exit Polls

Whether you're pleased or dejected this morning, I think there's very few of us who aren't stunned by the result in the general election yesterday.  In particular, polling was way off—even exit polls, which are supposed to take the pulse of voters as they leave the booth.  How did they get the result so badly wrong?  (Pre-count models showed Clinton with an average of about 300 electoral votes, and winning about 80 percent of the time.)

I'd guess that there are a number of factors (aside from the conspiracy theories, GOP or Dems):
  1. People were embarrassed to admit voting for Trump (i.e., he was viewed as the less respectable candidate), but that shame didn't translate to the actual ballot. That doesn't mean that people voted for Trump on a whim; it just means that they weren't keen on admitting that to someone else, even a pollster they'd never see again.
  2. Exit polling was not done at all locations, for obvious reasons. So projections were based on a regression analysis that fits estimates to the sampled locations. That regression assumes, among other things, a certain degree of polarization between demographics. It looks like that polarization was even more extreme than expected (which was already significant).
  3. Trump was simply a higher-variance candidate than the traditional Republican. This strategy makes sense in any contest where you're the underdog (as Trump was for most of the time)—if he were to play a low-risk strategy, he was almost guaranteed to lose. Employing a high-risk strategy increases the probability of a blowout loss, but it also increases the probability of a close win, which is what happened. We're seeing this all the time in sports, where endgame strategies by the trailing team are becoming more aggressive. That increase in variance translated to the polls. Five thirty-eight was very open about this—they pointed out that their model, though predicting a Clinton win, had about three times more variation (by some metric) in it than in past years.
I don't think fraud played any significant role in this election. We're seeing real disquiet with the state of the nation. Whether that disquiet has a basis in fact is immaterial as regards the result of the election.

I may have more to say about the election results themselves, but I'll save that for another post. 

[Most of this post was drawn from a Facebook comment.]

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