… Individual House races are fairly hard to predict. They don’t get all that much polling. Sometimes the candidates make a big difference, and sometimes they don’t. There will be lots of idiosyncratic and even “surprising” demographic patterns that emerge on Nov. 6, but the whole reason they’ll be surprises is because we won’t know about them ahead of time.
What this means is that Democrats will almost invariably lose some of the toss-ups, perhaps along with a couple of the “lean D” races, even if they’re having a pretty good night on Nov. 6. Unless we’re really, really lucky, the races just aren’t going to wind up in the exact order our model lists them or in the exact order that the Democratic Congressional Campaign Committee and National Republican Congressional Committee expect.
So it greatly helps Democrats that they also have a long tail of 19 “lean R” seats and 48 “likely R” seats where they also have opportunities to make gains. CONT.
Nate Silver, FiveThirtyEight