Thursday, April 10, 2008

Bill James Explains

My friend Bob Page spotted a great Q&A with one of the most interesting “numbers guys” around, Bill James. His specialty is baseball statistics, but what makes him special is a rare combination of quantitative depth and the ability to communicate that depth in accessible, interesting ways.

Bob’s blog post pulled a few choice quotes, which I won’t repeat here. However, I’ll add a few more:

People who think that they know when a manager should bunt and when a manager should pitch out and when a manager should make a pitching change are amateurs. People who have actually studied these issues know that the answer disappears in a cloud of untested variables.

On quantification of defense versus offense:

The interesting question is why defense is so much more difficult to quantify than offense in all sports. Perhaps defense by its nature involves more interaction between individuals than individual actions, and perhaps the way to get past that is to embrace the concept and measure combinations of players.

And finally here’s a quote from a recent article by James in Slate, about his theory for when a college basketball game is decided. It involves a percentage for how safe a team’s lead is, based on time left, point differential, and ball possession. A 100% safe lead is one that cannot be overcome.

The theory of a safe lead is that to overcome it requires a series of events so improbable as to be essentially impossible. If the “dead” team pulls back over the safety line, that just means that they got some part of the impossible sequence—not that they have a meaningful chance to run the whole thing.

That’s classic Bill James: explaining a theory of his own making, which involves a subtle statistical point, in two sentences that anyone can understand.

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