Monday, March 12, 2012

Expect Polling Variation

The new ABC/Washington Post poll this morning has produced a ton of buzz (at least as far as I can tell from my twitter feed) because Barack Obama's approval rating fell from 50% in their last poll to 46% in this one.

Everyone cut it out! It's almost certainly noise. Pollster's current average prior to this poll was sitting at 47.4%. This one is 46%. There's nothing to explain!

Look, for example, at the Gallup daily tracking poll, which last week went from 48% approval down to 43% and then back up to 48. Did Obama suddenly become significantly less popular in the middle of the week and then suddenly regain his strength? Of course not. It's just random movement.

This isn't complicated. There are lots and lots and lots and lots of polls out there. Some of them are going to be a bit high and others will be a bit low, just as if you flip an honest coin in sets of 100 flips you'll get some sets with 55 heads and others with 45 heads. The math says that we expect to get some 55s and some 45s. And the math says that we should expect for approval numbers or horse race numbers to vary around whatever the true value is (which, in turn, is probably best guessed at by using the poll-of-polls approach that Pollster uses). I understand that people need to react to specific polls, rather than slow changes in polling averages, but in this case there's really very little going on that I can see.

5 comments:

  1. Actually, it's VERY complicated, but also, very elegant, very cool, and very much possible to get a good enough understanding of to not muck it up like journalists tend to.

    What it certainly isn't, apparently, is intuitive. Hence Mark Twain's dictum.

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  2. For what it's worth, today's Gallup numbers go in exactly the opposite way from the Post poll, showing spikes in job approval for the President, along with a substantial increase in economic confidence. As Mr. Bernstein says, and as The Grinch said as well, "noise, Noise, NOISE, NOOIIISE, NOOOOOIIIIIIISSEE."

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  3. And of course, the cable news talkers have spent darn near the entire day mulling over the significance of this one poll as if it is some groundbreaking thing.

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    Replies
    1. Well, Anon, to quote a great novel, "tomorrow is another day."

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  4. http://www.businessinsider.com/cbs-poll-obama-approal-rating-down-to-41-2012-3

    The better spin is is today's hyper partisan enviornment, presidental approval polls are pretty meaningless.

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