Tuesday, September 25, 2012

Analyzing The World

Business Insider looks at a dozen of the insights in Nate Silver's new book, The Signal and the Noise (h/t Ritholtz).  A couple of my favorites:

The National Weather Service makes one of the best models in the world

The weather — "the epitome of a dynamic system" — has been increasingly predictable due to the National Weather Service's use of modeling on supercomputers. They've halved the average error in a temperature forecast since 1970, and they've been able to cut down the average error in the location of hurricane landfall from a 350 mile radius to a 100 mile radius in a mere 25 years.
Their calibration is as near to perfect as can be expected when it comes to forecast probability: "When they say there is a 20 percent chance of rain, it really does rain 20 percent of the time."

Your local meteorologist is horrible at his job, though

The Weather Channel isn't all that great — Silver notes that when they say there is a 20% chance of rain, it's only rained about five percent of the time. It's because "people notice one type of mistake — the failure to predict rain — more than another kind, false alarms," and the Weather Channel would rather err on the side of not ruining picnics.
But local TV meteorologists take this to an extreme. They're much more likely to overstate the probability of rain — in fact, "when a Kansas City meteorologist said there was a 100 percent chance of rain, it failed to rain one third of the time. "
First off, I never understood why the Republicans push to get rid of the National Weather Service, except that they are too hung up on privatizing everything.  Most of the private weather services just use the National Weather Service's predictions.   I've also never understood why the weathermen put out a 100% chance of rain prediction.  I mean, 80% sounds like it is very likely to rain, and it still gives you 20% of cover your ass insurance if it doesn't.  Why get so bold.  I also really liked the Deep Blue-Kasparov bit.

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