Pollster.com: About that Des Moines Register Iowa Poll

October 09, 2007

About that Des Moines Register Iowa Poll

NBC's First Read said it best: No Iowa poll "gets (and deserves) more attention than the Des Moines Register poll by ace Iowa pollster Ann Selzer." That reputation was earned, in part, from their final 2004 pre-caucus survey, the only public poll to correctly predict the rank order of the top four Democratic candidates. Political web sites have been buzzing since Sunday about their latest release, which to the credit of all involved includes a "methodology and questions" page that answers many of the questions asked by our Pollster Disclosure project. Today, Ann Selzer provides us with a few additional answers.

Their methodology page includes the full text of the substantive questions asked, plus a reasonably complete general description of how they selected "likely caucus goers." Follow the link for full details, but the gist is that they started with a random sample of telephone numbers drawn from "the Iowa secretary of state's voter registration list." They then interviewed those who said they would "definitely" or "probably" attend the caucuses on a question that offered those two choices plus one more ("probably not").

Selzer also informs us via email that their completed interviews included a small number of voters interviewed on their cell phones. They sent their original sample to a service that identified the known cell phone numbers among those provided by the secretary of state. Selzer dialed those numbers separately.

The data released on the Des Moines Register site did not address two questions we have been asking pollsters as part of our Disclosure Project. The first involves the percentage of adults represented by the each sample. In other words, how tight was the screen?

Ann Selzer has provided an answer via email. I will spare you the wonky math: The Democratic sample represents roughly 12%, and the Republican sample 10%, of Iowa's voting age population.

While the Register did not include data on the demographic composition of their samples on their results pages, the Register's David Yepsen (via First Read), included some of this information in his Sunday column:

Among likely Democratic caucusgoers, 62 percent are women, and Clinton carries more of them - 34 percent - than any other candidate...

Only 2 percent of likely Democratic caucusgoers are under age 25, while 51 percent are over age 55. On top of that, only 23 percent of the Democrats say this will be their first caucus...

[T]he poll shows 49 percent of the likely Democratic attendees are from rural and small-town Iowa. Among Republicans, 54 percent say they live in those places...

Among likely Republican caucusgoers, 51 percent describe themselves as "born again" or fundamentalist Christians...

A majority of GOP caucusgoers - 58 percent - are men, a contrast with the 62 percent female majority among Democrats...

Among Democrats, 76 percent have at least some college or more and 56 percent of them earn more than $50,000 a year. Among Republicans, 80 percent have some college or more and 60 percent earn more than $50,000.

We will have more on returns from the Disclosure Project later in the week.

-- Mark Blumenthal

October 09, 2007 in Disclosure, Iowa

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Comments

FlyOnTheWall:

I'm no expert, but I'm deeply concerned about undersampling of voters aged 17-25. Selzer turned up just 8 of them in her sample who intended to attend the caucus. Her stress on obtaining cell phone numbers indicates to me that she, too, is concerned that she may be undersampling this demographic.

Here's the problem: in the 2006 general election, hardly a sexy race likely to attract marginal voters, the 18-24 slice of the electorate accounted for 4% of Democratic poll goers. Widen that to include 17-25, and you're probably talking about 5% of the voters, in an election that included no massive GOTV campaign targeting youth voters, no particularly appealing candidates, and, most-crucially, which was held during the school year, not during vacation.

If you can hit 4-5% in an off-year general, it's absurd to think that the percentage would be just half that in the caucuses. Moreover, the Register's discussion of the results is misleading. It trumpets the fact that 51% of likely caucus-goers are over the age of 55 - but the statewide statistics show that fully 65% of voters in 2006 were over the age of 50. If anything, the AARP demographic is comparatively *under*-represented in caucuses, perhaps because of decreased mobility.

Want more cause for concern? Voters age 18-25 account for about 10% of registered Democrats. With a 12% screen, that means that Selzer called about 332 registered voters in that demographic, and found only 8 who intend to vote. The problem here is that many voters that age are attending college, but they'll be home on vacation when the caucus takes place. They're less likely than ever to respond to phone polls, but more likely than in past years to show up. It all adds up to a major headache for pollsters, and it's something I'd like to see them be much more up-front about.

Why not offer a simple disclaimer: "We believe our poll to be highly accurate concerning voters over the age of 25, but given the timing of this caucus and technological change, we don't have the first f#$@ing clue what voters younger than 25 are likely to do"?

Posted on October 11, 2007 6:06 PM

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