Green Room

National polls vs. Ohio polls: They can’t both be right

posted at 4:30 pm on October 28, 2012 by

Josh Jordan gauges the impending collision between the irresistible force of Romney’s national momentum and the immovable object of O’s small but stubborn lead in the Ohio polls. His take? The “immovable” object will move:

In Ohio, Republicans tend to outperform their share of the national vote: In the last six presidential elections, only in 2004 has the Republican candidate performed worse in Ohio than they did nationally, and even that was only a .3 percent difference. In the other five elections, the GOP candidate outperformed their margin of the national vote by an average of 3.1 percent. While it’s clearly possible for Republicans to perform worse in Ohio than nationally, it is very difficult to imagine a scenario where there is more than a point difference between them based on past elections. History would suggest Romney could not be up 2 points nationally while being down 2.1 in Ohio, which would mean Republicans would be under-performing in Ohio by over 4 points.

Democrats national turnout advantage is usually bigger than their Ohio turnout: Not since 1996, during Clinton’s reelection campaign, have Democrats had a larger turnout advantage in Ohio than nationally. In 2000 and 2008 Democrats were 2 points under their national turnout advantage and were actually 5 points under in 2004. Currently polls are showing an average Democratic turnout advantage of 6.3, which is 1.9 points higher than their current advantage nationally.

So why do most Ohio polls show O ahead? Because, says Jordan, there’s some subset of Democrats who are fibbing when asked by pollsters whether they’ve already voted. They know they’re supposed to — Obama’s been droning on about it nonstop — yet they haven’t. But when they lie and say they have, they automatically end up being counted as “likely voters,” which explains why you’re seeing Democrats oversampled in a lot of Ohio polls.

Really, this is common sense. How plausible is it that a guy who’s now below 47 percent in RCP’s national average is going to win a state that famously tracks with national sentiment each cycle? He’s getting hammered nationally with independents, especially on the core issue of the economy, and yet somehow he’s two points ahead overall in the ultimate bellwether? Really?

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