WSJ on Luck in Baseball

Russell Adams discusses extracting luck from baseball statistics in this weekend’s Wall Street Journal.

By tallying minute details about every hit ball, statistics gurus say they can compute how much of a player’s accomplishments stem from random factors. The results could affect which free agents should get top dollar after a great season and suggest which teams are likely to hold up in the pennant race.

I make an appearance to discuss ProPS (2006 numbers at The Hardball Times).

For J.C. Bradbury, economics professor at the University of the South in Sewanee, Tenn., the desire to understand the role of chance in baseball started with a slump. In 2004, Atlanta Braves star Chipper Jones’s hitting numbers were suffering. Even though Mr. Jones appeared to be hitting the ball well, he wasn’t getting on base or hitting for power at his normal rate.

So Prof. Bradbury looked for statistics that would isolate the hitter’s role in each at-bat — and exclude the performance of the pitcher and fielders. The starting point was a mound of data on the characteristics of each ball put into play by Mr. Jones. Based on historical data on balls hit in similar ways, Prof. Bradbury estimated what should have happened, statistically speaking, in Mr. Jones’s at bats.

In this approach, a ball hit on a trajectory that would typically send it past the fielder for a base hit counted as a hit for Mr. Jones regardless of whether he was called out in real life. Turns out, there were many such instances for Mr. Jones. Prof. Bradbury concluded the Braves star was suffering from a run of bad luck — an indication he was likely to perform significantly better the next season. Indeed, in 2005, Mr. Jones’s batting average bounced back to .296 from .248. “I was quite surprised at how well it predicted player performance,” says Prof. Bradbury.

This topic interests me very much, and think Russell does an excellent job of covering the topic. I’d like to thank him for including me in the article.

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