The pre-election polling averages (not the FiveThirtyEight forecasts, which also account for other factors) in the 10 most competitive Senate races had a 6-percentage point Democratic bias as compared to the votes counted in each state so far…

The bias might narrow slightly as more votes are counted; late-counted votes tend to be Democratic in most states. Still, this is a big “skew,” and it comes on the heels of what had been a fairly substantial bias in the opposite direction in 2012. The polls — excepting Ann Selzer’s — are having some problems.