All That’s Silver Does Not Glitter
posted at 6:15 pm on July 25, 2012 by Mitch Berg
While the national polls show the presidential race a statistical toss-up, Nate Silver points out that polls conducted in swing state show Obama with an actual lead of sorts – around three points:.
While that isn’t an enormous difference in an absolute sense, it is a consequential one. A one- or two-point lead for Mr. Obama, as in the national polls, would make him barely better than a tossup to win re-election. A three- or four-point lead, as in the state polls, is obviously no guarantee given the troubles in the economy, but it is a more substantive advantage.
Here’s the part that caught my attention; I’ve added emphasis:
The difference isn’t an artifact of RealClearPolitics’s methodology. The FiveThirtyEight method, which applies a more complicated technique for estimating polling averages, sees broadly the same split between state and national polls.
On the one hand – well, doy. Obama’s an incumbent elected in a wave, protected by a media that serves as his Praetorian Guard. Of course he’s going to be polling well.
On the other hand? My real point in this article is the abovementioned “FiveThirtyEigtht Method”.
I addressed this two years ago - when Silver, who is generally acknowledged to be a moderate Democrat, spent most of the 2010 campaign predicting a 6+ point Mark Dayton victory.
How did he arrive at that number?
- By taking an assortment of polls from around MInnesota, conducted by a variety of polling operations, and…
- Applying a weighting to each poll, the “538 Poll Weight”, which came from an unexplained formula known, near as I can tell, only to Silver. Which is not to say that it’s wrong, or statistically, intellectually or journalistically dishonest, per se - merely that it’s completely opaque
But let’s take Silver’s methodology at face value – because he’s a respected statistician who works for the NYTimes, right?
The fact remains that, at least here in Minnesota, two of the polls that were given great weight in Silver’s methodology – the Star Tribune “Minnesota” poll and the Hubert H. Humphrey Institute poll, are palpably garbage, and should be viewed as DFL propaganda at best, calculated election fraud at worst.
We went through this in some detail after the 2010 election: there’s an entire category on this blog devoted to going over the various crimes and misdemeanors of Twin Cities media pollsters. ,Long story short – since 1988, the Strib “Minnesota” poll has consistently shorted Republican support in polls, especially the polls closest to the elections, especially in close elections. The “Minnesota” poll’s only redeeming point? The Humphrey Institute poll is worse. In both cases, they tended – moreso in closer races – to exaggerate the lead the Democrat candidate for Governor, Senator or President had. For example, in 2010 both polls showed Mark Dayton with crushing, overwhelming, humiliating leads over Tom Emmer on election-eve. It ended up the closest gubernatorial race in Minnesota history. The “Minnesota” poll was so bad, Frank Newport of Gallup actually wrote to comment on its dubious methodology. I suspect that the results are less mathematical background noise or methodological quicks – which would, if truly random, show distortions that would even out between the parties over time. While it’s not provable without a whistle-blower from inside either or both organizations, I suspect the results shake out the way they do, if you are inclined to believe people have integrity, due to selection bias in setting up survey samples (and, if you don’t have much faith, in systematic bias working to achieve a “Bandwagon Effect” among the electorate. Count me among the cynics; an organization with integrity would have noticed these errors long before a guy like me who maxed out at Algebra I in college and fixed the problem. I’m willing to be persuaded, but you’ll have to have a much better argument than most of the polls’ defenders).
The point being, this is the quality of the raw material that leads Nate Silver to his conclusions. And that should give Silver, and people who pay attention to him, pause. I don’t know if the other state polls are as dodgy as Minnesota’s local media polling operations.
That’d be a great subject for a blogswarm.
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