Sam Wang of the Princeton Election Consortium thinks that Democrats currently have a 72 percent chance of retaining control of the Senate this year. Most other forecasting outfits think Republicans have a 60-70 percent chance of winning control. Why the difference?
In most cases, added assumptions (i.e. special sauce) have led the media organizations to different win probabilities — which I currently believe are wrong....The major media organizations (NYT, WaPo, 538)...all use prior conditions like incumbency, candidate experience, funding, and the generic Congressional ballot to influence their win probabilities — and opinion polls.
....Longtime readers of PEC will not be surprised to know that I think the media organizations are making a mistake. It is nearly Labor Day. By now, we have tons of polling data. Even the stalest poll is a more direct measurement of opinion than an indirect fundamentals-based measure. I demonstrated this point in 2012, when I used polls only to forecast the Presidency and all close Senate races. That year I made no errors in Senate seats, including Montana (Jon Tester) and North Dakota (Heidi Heitkamp), which FiveThirtyEight got wrong.
I'd sure like to believe this. PEC is my go-to political polling site, after all. But it sure doesn't feel like Democrats are in the driver's seat right now, does it? All of my political instincts scream that Wang's forecast is wrong.
That's probably because I'm a pessimist by nature. But you either believe in poll aggregation or you don't. I do, and PEC has performed well in every election for the past decade. So just as I wouldn't "deskew" bad poll results I didn't like, I guess I won't try to second-guess good poll results that don't seem quite right. If Wang thinks Democrats are currently favored to keep control of the Senate, then so do I.