… Last month, I examined the possibility that Senate polls could prove to be biased or “skewed” against Democrats. If the polls have even a modest bias against Democrats, the party’s chances of keeping the Senate would be more like 50-50. And if the polls have a more severe anti-Democratic bias, it would be favored to keep its majority.
There is, indeed, some precedent for this, and we don’t have to go back far. CONT.
Nate Silver, FiveThirtyEight