Tuesday, October 25, 2016

Two Weeks Out

Is the race over?  Superstitious folk and pollsters with long memories (1936 and 1948) say never say it is, but it’s hard to imagine anything other than a giant meteor changing the trajectory of the race.

There are those who are going around saying yes it’s over; Hillary Clinton has a 93% chance of winning, according to the New York Times Upshot.  I prefer to go with the people at FiveThirtyEight who are a little less convinced (although still convincing) with an 86.3% chance.

fivethirtyeight-pollsonly-10-25-16The Oracle speaks:

As I wrote last week, Hillary Clinton is probably going to become the next president. But there’s an awful lot of room to debate what “probably” means.

FiveThirtyEight’s polls-only model puts Clinton’s chances at 85 percent, while our polls-plus model has her at 83 percent. Those odds have been pretty steady over the past week or two, although if you squint you can see the race tightening just the slightest bit, with Clinton’s popular vote lead at 6.2 percentage points as compared to 7.1 points a week earlier. Still, she wouldn’t seem to have a lot to complain about.

Other statistical models are yet more confident in Clinton, however, variously putting her chances at 92 percent to 99 percent. Maybe that doesn’t seem like a big difference, since people (wrongly) tend to perceive odds above 80 percent as sure things. But flip those numbers around, and instead of Clinton’s chances, consider Donald Trump’s. The New York Times’s Upshot model gives Trump an 8 percent chance of winning the election. Our models say a Trump presidency is about twice a likely as The Upshot does, putting his chances at 15 percent (polls-only) and 17 percent (polls-plus). And our models think Trump is about four times as likely to win the presidency as the Huffington Post Pollster model, which puts his chances at 4 percent.

So let me explain why our forecast is a bit more conservative than some of the others you might be seeing — and why you shouldn’t give up if you’re a Trump supporter, or assume you have it in the bag if you’re voting for Clinton. We’ve touched on each of these points before, but it’s nice to have them in one place. I’ll also show you what probability our model would give to Trump and Clinton if we changed some of these assumptions.

TLDR: 1) A lot of voters are still undecided; 2) The model is calibrated on general elections since 1972; 3) The models are allowing for more unlikely events (giant meteor, perhaps?); 4) State outcomes are correlated with one another.

As we say frequently, the greater uncertainty in the FiveThirtyEight forecast cuts both ways. So while we show a greater likelihood of a Trump win than most other models, we’d also assign a greater possibility to a Clinton landslide, in which she wins the election by double digits. But while the campaign is almost over, the suspense isn’t quite done.

In other words, if you can’t bear the suspense, you still have the World Series (which Nate pegs the Cubs as favored to win) or the new TV season to distract you.

2 barks and woofs on “Two Weeks Out

  1. Joe Scarborough, that font of Republican historical wisdom, says that if you’re behind as much as 5 points you’re toast. Even a four point gap means you’ve lost. So, please, can’t we just declare a winner and get this damned election season over? Ah, but remember the Congress and Clinton still needs to secure a majority in the Senate so her judicial appointments can stand a chance. Slog on . . .

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