Mansfield Fox

Law student. Yankees fan. Massive fraggle. Just living the American dream.

Monday, November 07, 2005

Innumeracy in Action

The real reason I love watching sports analysis shows on TV is that I can't get enough of the sight of ex-athletes in unbelievably gaudy suits. Without Michael Irvin, I don't know how I could go on.

But a close second is the mildly sadistic pleasure I get from watching the parade of utter ignorance regarding statistics. See, I don't have much of a "head for numbers", and I never studied statistics in high school or college, unlike many of my law school classmates. But I might as well be a Fields Medal winner compared to your average sports commentator.

Case in point: on ESPN's "Cold Pizza" morning show just now, one of the experts just breathlessly announced that the Oakland Raiders needed to run more plays through their running back LaMont Jordan. Why? Because the team is 3-0 in games in which Jordan rushes 20 or more times, and 0-5 in games in which he rushes 19 or fewer times.

Now, this is (I think) a pretty basic correlation/causation confusion. There's a correlation between Jordan rushing 20 times and Oakland winning, but that's no guarantee of a causal relationship. Indeed, the most likely explanation is that Jordan gets more rushes in games that Oakland is leading in the fourth quarter as the team tries to run out the clock, and that he rushes less in games where Oakland is behind and trying to mount a comeback and turns to the passing game as a way to preserve game time. (I quickly perused the boxscores on, and this does indeed seem to be what happened.)

Just a quick reminder that not all magical thinking involves rabbit's feet.