Senate Prognosis
By Good roundup from Sam Wang. Essentially, models that combine fundamentals with polling data continue to favor the Republicans. The polling data itself favors Democratic retention of the Senate. Since Wang is in the latter camp, his bottom line:
The PEC polling snapshot has mostly favored Democrats. Starting from June 1st, Democrats have led for 61 days and Republicans for 26 days, a 70-30 split. During that period, the Senate Meta-Margin has been D+0.24±0.57%. Assuming that the June-August pattern applies to the future, I can use this Meta-Margin, and the t-distribution with 3 d.f., to predict the future, including the possibility of black-swan events. The result is that the November Senate win probability for the Democrats (i.e. probability that they will control 50 or more seats) is 65%.
I’m not endorsing Wang over Silver, Sides et al.; just an interesting difference.