Academic

The Epistemology of Baseball (or, Joe Torre and an actuary walk into a bar...)

By Mark Weidemaier

... where, of course, they watch a baseball game. Let's say it's the bottom of the 9th inning, the game is tied with no one out, and there's a runner on first base. Should the home team bunt?

The bartender asks Joe Torre (the famous baseball manager), who replies: "You should always bunt in this situation. Everyone knows that!" And he's right - if, by "everyone," you mean people commonly recognized as baseball "experts": players, coaches, and sports journalists.

The actuary would likely give a different answer, something like "Meh," or "Bunting would be silly." That's because, historically, teams that occupied the position the bunt is designed to achieve (bottom of the 9th, tie game, runner on 2nd, one out) have won a modestly lower percentage of their games than those that occupied the position the home team is now in. In fact, historical data shows that many commonly-employed baseball tactics often decrease the probability that the team employing the tactic will win. Yet these tactics persist. (You can play along at home here.)

None of this is news to readers of Moneyball, which described the inefficiencies that exist (now to a lesser degree) in the market for baseball players. There is a vast amount of evidence, across a wide range of predictive domains, that formal, data-driven methods of prediction out-perform the kinds of impressionistic judgments that so-called experts often make. Yet despite the strength of this evidence, experts in the relevant fields often ignore or outright reject the evidence. And how would you expect Joe Torre to feel when told that, despite his vast experience, he can't perform as well as an actuary who has never even attended a game?

What does this have to do with law? At least a little, as I'll suggest in a later post.   

Full post as published by The Faculty Lounge on July 07, 2009 (boomark / email).