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Latest Defense of Nate Silver: Even When He’s Wrong, He’s Right

At this point in the election, both the national tracking polls and, generally speaking, the battleground state polls show an extremely close race. This has inspired much criticism of stat-man Nate Silver. Liberals, as Jonathan wrote recently, may be looking for a scapegoat if Barack Obama loses, and will wonder why Silver insisted that statistically Obama was an overwhelming favorite to win re-election right up to the end. Conservatives say that statistics don’t factor in momentum, that any predictive model that ignores trends should be taken with a grain of salt, and that current trends don’t back up Silver’s predictions of Obama as the heavy favorite.

Additionally, as Josh Jordan has pointed out at National Review Online, there are problems with Silver’s statistical model, which gives more weight to pro-Obama polls—even older polls—than to those showing Mitt Romney’s recent gains. Silver’s defenders respond that Silver makes no guarantees, and that giving Obama a high chance of winning doesn’t preclude the opposite outcome. This defense—essentially that no outcome can disprove Silver’s model—treads a bit too close for comfort to Chuck Klosterman’s classic rant about statistics:

Life is chock-full of lies, but the biggest lie is math. That’s particularly clear in the discipline of probability, a field of study that’s completely and wholly fake. When push comes to shove–when you truly get down to the core essence of existence–there is only one mathematical possibility: Everything is 50-50. Either something will happen, or something will not.

When you flip a coin, what are the odds of it coming up heads? 50-50. Either it will be heads, or it will not. When you roll a six-sided die, what are the odds that you’ll roll a three? 50-50. You’ll either get a three, or you won’t. That’s reality. Don’t fall into the childish “it’s one-in-six” logic trap. That is precisely what all your adolescent authority figures want you to believe. That’s how they enslave you. That’s how they stole your conviction, and that’s why you will never be happy. Either you will roll a three, or you will not; there are no other alternatives. The future has no memory. Certain things can be impossible, and certain things can be guaranteed–but there is no sliding scale for maybe. Maybe something will happen, or maybe it won’t….

Quasi-intellectuals like to claim that math is spiritual. They are lying. Math is not religion. Math is the antireligion, because it splinters the gravity of life’s only imperative equation: Either something is true, or it isn’t. Do or do not; there is no try.

Klosterman was being sardonic (probably?) but much of this argument over Silver’s model feels that way too. Both sides warn against putting too much stock in Silver’s model because it’s only numbers. Here is Ezra Klein’s defense of Silver:

It’s important to be clear about this: If Silver’s model is hugely wrong — if all the models are hugely wrong, and the betting markets are hugely wrong — it’s because the polls are wrong. Silver’s model is, at this point, little more than a sophisticated form of poll aggregation.

But it’s just as important to be clear about this: If Mitt Romney wins on election day, it doesn’t mean Silver’s model was wrong. After all, the model has been fluctuating between giving Romney a 25 percent and 40 percent chance of winning the election. That’s a pretty good chance! If you told me I had a 35 percent chance of winning a million dollars tomorrow, I’d be excited. And if I won the money, I wouldn’t turn around and tell you your information was wrong. I’d still have no evidence I’d ever had anything more than a 35 percent chance.

That basically boils down to: Don’t blame Silver if he’s wrong, because he’s relying on other people’s work, and no matter what happens, Silver wasn’t wrong, because he said it could happen, and it did.

If Mitt Romney wins, does that discredit Nate Silver? Only if you defied Silver’s advice, and that of his defenders, not to rely on him in the first place.