I don't believe Nate Silver pointed out that the polls undercounted democrats, do you have a cite? In fact his analysis was basically that the aggregate polling "got it right", coming very close to the final counts in almost all cases.
In the four victory-critical states I still have in my head, Silver's polling averages (which weren't very much different from Wang's or TPM's or RCP's, by the way) nailed it dead on in Florida, undercounted Democrats in Colorado and Virginia, and overcounted them in Ohio. But in no case were the errors more than 1.5% or so.
In the four victory-critical states I still have in my head, Silver's polling averages (which weren't very much different from Wang's or TPM's or RCP's, by the way) nailed it dead on in Florida, undercounted Democrats in Colorado and Virginia, and overcounted them in Ohio. But in no case were the errors more than 1.5% or so.