By Daniel Engber:
It’s well after midnight on the East Coast, and the results are in: Nate Silver has won the 2012 presidential election by a landslide. His magic formula for predictions, much maligned in some corners in recent weeks, appears to have hit the mark in every state—a perfect 50 green M&Ms for accuracy. Now my Twitter feed is blowing up with announcements of his coronation as the Emperor of Math and the ruler of the punditocracy. Wait—it was even more than that, they say: a victory for blogging, and also one for rational thought. He proved the haters wrong! He proved science right! Is this guy getting lucky tonight or what?
But all these stats triumphalists have it wrong. Nate Silver didn’t nail it; the pollsters did. The vaunted Silver “picks”—the ones that scored a perfect record on Election Day—were derived from averaged state-wide data. According to the final tallies from FiveThirtyEight, Obama led by 1.3 points in Virginia, 3.6 in Ohio, 3.6 in Nevada, and 1.9 in Colorado. He won all those states, just like he won every other state in which he’d led in averaged, state-wide polls. That doesn’t mean that Silver’s magic model works. It means that polling works, assuming that its methodology is sound, and that it’s done repeatedly.