While I am currently predicting a gain of 72 House seats for the Republicans, the polls say that much larger gains are possible. RCP currently shows the GOP ahead by an eight-point margin. My own model shows a 7.7 percent margin. That converts into 242 to 259 House seats for the GOP, a gain of 64 to 81 seats.
However, in recent days Gallup showed the Republicans up by a 15-point margin, Fox News had them up by 13, and CNN/Opinion Research by 10 points. What if Gallup is correct and the Republicans win by a 55 to 40 margin?
According to my most generous model, my 40-year model (see details of the models here), the Republicans would end up with 295 House seats, a gain of 117 seats. My other models show the GOP finishing with 263 seats (+85 seats) or 273 seats (+95 seats) if Gallup is correct. The average of the three models, which I’ve been using for my middle-of-the-forecast, shows a GOP gain of 99 seats to 277 seats if Gallup is correct.