Pollster.com: Frankovic on Iowa's "Challenge For Pollsters"

November 28, 2007

Frankovic on Iowa's "Challenge For Pollsters"

Kathy Frankovic, the director of surveys for CBS News, devotes her latest column to a subject regular readers know well: The Iowa caucuses and the special challenges they create for pollsters. Frankovic has long been a central player in the network consortium that conducts exit polling, so we should pay particular attention to one particular comment she makes about the limitations of past Iowa Caucus entrance polls:

In typical exit polls, tallies of the gender, race and apparent age of those not responding to the interview request are kept, and it is possible to adjust (and correct) the responses for those demographics. Historically, the largest non-response in exit polls has come from older voters. This often doesn't matter; it shouldn't matter if there is no difference in whom older and younger voters support. But historically that correction hasn't been made in the Iowa entrance polls. And this year, on the Democratic side, there is an age difference in candidate support. In the CBS News/New York Times Iowa poll, younger caucus goers -- those under the age of 45 -- favor Barack Obama: he gets 39 percent of their support, and Hillary Clinton 24 percent. The oldest caucus-goers -- those over 65 -- favor Clinton over Obama, 30 percent to 11 percent. Pre-election polls show less of an age difference among Republican caucus-goers.

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.

PS: CBS has also recently launched a new feature, in partnership with the Roper Center, that provides a free, searchable archive of all questions asked on all CBS News surveys conducted since January 2007. That is a resource worth bookmarking.

-- Mark Blumenthal

November 28, 2007 in Exit Polls, Iowa, The 2008 Race

Comments

p. lukasiak:

those under the age of 45 -- favor Barack Obama: he gets 39 percent of their support, and Hillary Clinton 24 percent. The oldest caucus-goers -- those over 65 -- favor Clinton over Obama, 30 percent to 11 percent.

which of course begs the question of why you follow the corporate media in defining the Democratic Primary as a two candidate race -- even in Iowa.

I mean, while it may be understandable to report ONLY the results of Obama/Clinton for those under 45, insofar as they have 73% of the reported support.

But, those two only have 41% of support from voters over 65 -- and while you acknowledge that older voters are more likely to attend caucuses, you completely ignore the question of who the 59% of the most likely caucus goers will be supporting.

I think we should be able to expect better from independents like you -- you don't have to follow the pre-determined media narrative that excludes everyone but Obama and Clinton, you can actually REPORT THE RESULTS WITHOUT BIAS.

Posted on November 28, 2007 10:50 PM

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kwo:

Ah, so not only will the entrance polls be wrong, but the younger voters (who didn't turn out in 2004), will be underrepresented by the screwy Iowa caucus "weighting" rules?

Posted on December 19, 2007 6:47 PM

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