Not All Forecasting Models are Equal

Nate Silver: “I don’t like to call out other forecasters by name unless I have something positive to say about them — and we think most of the other models out there are pretty great. But one is in so much perceived disagreement with FiveThirtyEight’s that it requires some attention. That’s the model put together by Sam Wang, an associate professor of molecular biology at Princeton.”

“That model is wrong — not necessarily because it shows Democrats ahead (ours barely shows any Republican advantage), but because it substantially underestimates the uncertainty associated with polling averages and thereby overestimates the win probabilities for candidates with small leads in the polls.”

Kevin Drum: “If Wang’s prediction of this year’s Senate race turns out to be more accurate than Silver’s, I almost hate to think what might happen. Silver’s head is going to explode or something. In any case, this is far more fun than you normally get from a couple of geeky poll aggregators.”