Wednesday, June 30, 2010

Senate Forecasts

Nate Silver updated his senate forecast and the Democrats are now projected to have 55.2 seats come November, Republicans 44.2.  He also projects 0.6 Charlie Christs which I think is funny (expected value how cool are you).

What’s really interesting from a geek political perspective is the war brewing between Silver and Research 2000 (R2K), a polling company.  Daily Kos is suing R2K alleging that they fake their polling data, and Nate’s right there supporting the Kos with cool graphs like these showing the difference in week to week changes between R2K and Gallup.

Remember your normal distribution.  If I’m a polling company and I want to fake data, I never pick the same value (hence no 0’s in the left) and I add 1 or subtract 1 every week so it looks like it changes.  But if I’m sampling data, I vary normally which is the nice bell curve on the right.

The point is that not all polling companies are the same.  Nate’s been trying to point this out, the media doesn’t care, and he’s been starting a campaign for the political rating industry to grade polling companies based on performance.  Anyways, you can follow the drama at his blog

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