Kentucky
Silver Mines, on the disconnect between reality and polling in KY-GOV:
It’s not yet clear whether pollsters simply projected that more Democratic voters would show up than actually did or whether undecided voters broke overwhelmingly for the Republican candidates. The former suggests an electorate modeling problem that could be a big problem during the presidential primaries, when turnout is low. On the other hand, trouble modeling the electorate would be less of an issue in the 2016 general election, when turnout is at its highest.
However, if undecided voters broke toward the Republicans and the “fundamentals” — Kentucky is a very Republican-leaning state in federal elections — that could be a sign that a candidate hitting 50 percent in general election polls is a bigger deal than we previously thought. Remember, polls showed Democrat Mark Warner winning the 2014 Virginia Senate race easily with 50 percent of the vote; Warner earned almost exactly 50 percent, but he barely won.
There is a third option.
Which happens to be what turned out to be the correct explanation to last year’s disconnect between reality and polling.
People who intended to vote for Bevin and other Republican statewide office candidates all along were not honest with pollsters, passed themselves off as undecided when polled.
I think the real explanation, at least in this instance, is a combination of assuming a higher Democrat turnout than reality, overpolling Democrats of the nature of the selection biases of pollsters, and Republicans passing themselves off as undecideds.

