FiveThirtyEight - Nate Silver\'s Political Calculus
November 3, 2010, 9:33 pm
Did Polls Underestimate Democrats’ Latino Vote?
By NATE SILVER

The two Senate races where the actual winner was different from the leader in our polling-based projections were Colorado and Nevada (it’s also probable that we’ll miss Lisa Murkowski’s victory in Alaska once all her write-in votes are — eventually — counted).

The miss in Colorado wasn’t bad — our forecast had Michael Bennet as about a 1-point underdog, and he won by 1 point instead, although there are still a few votes left to count.

In Nevada, however, where most polls showed Sharron Angle ahead and Harry Reid instead won by almost 6 points, the polls were pretty far off the mark. Errors like that occur quite frequently in primaries and in House races, where the polling landscape is tougher. They also occur sometimes in lopsided races, which are more difficult to hit on the nose. It’s fairly unusual, however, to have the consensus of polls off by 7 or 8 points in an extremely competitive Senate or gubernatorial general election.

I riffed a little bit last night on why the public polls might have been wrong in Nevada; I speculated, for instance, that the fact that Mr. Reid is the sort of candidate whom one votes for unenthusiastically might have skewed the turnout models.

There is another theory, however, which was proposed to me last night by Matt Barreto of the polling firm Latino Decisions.

“There is one overarching reason why the polls were wrong in Nevada,â€