Continuing a six-part series. Part 1 covered basic elements of the caucus system, part 2 explained why so many Iowans can’t or won’t attend their precinct caucus, part 3 discussed how Democratic caucus math can affect delegate counts, and part 4 described how precinct captains help campaigns.
Measuring the horse race ahead of the Iowa caucuses poses special challenges, particularly on the Democratic side. Those problems affect even the Des Moines Register’s longtime pollster Ann Selzer, whom FiveThirtyEight.com has given an A+ grade and called “the best pollster in politics.”
Follow me after the jump to see why polling expert Mark Blumenthal has described the caucuses as a “pollster’s nightmare.”