The Problem With Polling Iowa

Pollster Mark Blumenthal has an interesting bit on how selection bias may be skewing the polls in Iowa:

The point here, in case it is not obvious: Non-response bias may have exaggerated the percentages of younger (under 45) caucus goers the 2004 Iowa entrance poll (something I wondered about a month or so ago). And since I’m assuming that age is strongly related to having attended a caucus in the past, the entrance poll estimate of the number of caucus newcomers in 2004 may be exaggerated as well.

Basically, older caucus-goers are less likely to talk with younger polltakers, which means that candidates like Dean or Obama that tend to have more support from younger voters look stronger in the polls than they actually are. The way in which the Iowa caucus system works heavily favors older voters who tend to be a part of the caucuses year after year. That’s why the results in Iowa may be vastly different from the way they’re portrayed—candidates like Obama don’t tend to have the same appeal to the typical Iowa caucus-goer as they do to the typical voter.

I’d be willing to guess that the story coming out of Iowa will be the resurgence of Hillary Clinton. Clinton’s made some major missteps in the last few months, but that’s made it easier for her to steal a page from her husband’s playbook and become the Comeback Kid—and with the latest CNN/WaPo poll putting her comfortably ahead in New Hampshire helps in painting a picture of a campaign on the upswing.

As for the Republican race, the effect of potential poll bias remains to be seen. It could be that Huckabee’s appeal to evangelicals matches with the target profile of Iowa caucus-goers. Or it could mean that Romney, McCain, or Thompson could get a boost from older voters. The race has been up in the air for weeks now, and the potential for change is so great that it’s simply impossible to make a worthwhile call.

Polling is never an exact science, which is why it only has limited utility in a campaign. A candidate like John Kerry who was in the single digits at this point in 2003 can suddenly sweep the nomination. A candidate like Howard Dean that appears unstoppable can end up losing big. Part of the fun in politics is in contests like this where anything could change. (Although it’s much less fun for those on the inside of a campaign.) The first rule of polling should be not to trust polling, as it’s as much of an art as a science. It’s quite possible that everything we’ve heard about the race in the last few weeks may be rendered moot when Iowans actually go into their caucuses and pick their candidates.

5 thoughts on “The Problem With Polling Iowa

  1. Hey Jay, did you see the latest CBS News poll out of South Carolina? Your boy Fred Thompson is coming in FIFTH PLACE! Pulling in only 10% of the vote! OUCH!

  2. Interesting analysis and info. i hope your right on Hillary’s upswing. I agree that Hillary’s support is underreported. heres hopeing she wins Iowa.

  3. Dismissing every poll as being inaccurate is the last refuge of losing campaigns before their inevitable concession speeches. You would think you’d have learned your lesson when you predicted last fall that there was NO WAY Amy Klobuchar would beat Mark Kennedy by 20 points in the Minnesota Senate race.

  4. Yes, let’s just let the pollsters decide elections – why bother to vote since the polls are infallible? After all, remember how Howard Dean swept John Kerry by 20%+ in Iowa in 2003, easily capturing the Democratic nomination?

    Polls are only as good as their samples, and trying to extract a meaningful statistical sample from a contest like Iowa is damn near impossible. The massive difference between the 2003 polls in Iowa and the actual results amply demonstrates that principle.

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