What I’ve been saying all along

- October 1st, 2012

I am a huge fan of Michael Barone. He understands American politics like very few people do. Also, he’s a recovering (his word) pollster. So when he says, beware the polls showing Obama ahead, we ought to listen.

First, some points about the limits of polls. Random-sample polling is an imprecise instrument. There’s an error margin of 3 or 4 percent and polling theory tells us that one out of 20 polls is wrong, with results outside the margin of error. Sometimes it’s easy to spot such an outlier; sometimes not.

In addition, it’s getting much harder for pollsters to get people to respond to interviews. The Pew Research Center reports that it’s getting only 9 percent of the people it contacts to respond to its questions. That’s compared with 36 percent in 1997.

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Are those 9 percent representative of the larger population? As that percentage declines, it seems increasingly possible that the sample is unrepresentative of the much larger voting public. One thing a poll can’t tell us is the opinion of people who refuse to be polled.

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I don’t believe that any of the media pollsters have been tilting their results in order to demoralize Republicans, though I do look with suspicion on the work of some partisan pollsters.

But I do have my doubts about whether samples with more Democratic Party identification than in 2008 are accurate representations of the electorate. Many states with party registration have shown big drops in registered Democrats since then.

Pollster Scott Rasmussen, who weights his robocall results by party identification, adjusted monthly, has shown a much closer race than most pollsters who leave party identification numbers unweighted. So has the Susquehanna poll in Pennsylvania.

It may be that we’re seeing the phenomenon we’ve seen for years in exit polls, which have consistently skewed Democratic (and toward Barack Obama in the 2008 primaries). Part of that is interviewer error: Exit poll pioneer Warren Mitofsky found the biggest discrepancies between exit polls and actual results were in precincts where the interviewers were female graduate students.

But he also found that Democrats were simply more willing to fill out the exit poll. Which raises the question: Are we seeing the same thing in this month’s polls?

I’m not a polling expert, but for what it’s worth, I believe that’s exactly what we’re seeing. So I take those polls showing Obama ahead of Romney with a great mountain of salt.

Categories: United States

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