Zimbalist reviews Bradbury, Bradbury responds

Famed sports economist Andrew Zimbalist has posted a review of two recent baseball economics books: Vince Gennaro's "Diamond Dollars," and J. C. Bradbury's "The Baseball Economist." The Bradbury review is of more interest to me, since I haven't finished Gennaro's book. Plus, Bradbury has responded to Zimbalist on his website.

Here's Zimbalist's review; here's Bradbury's response.

It seems to me that Zimbalist makes some good points, but also some very questionable ones. Bradbury defends himself well.

And my sympathy is with Bradbury, because Zimbalist doesn't know much about sabermetrics, and, for that reason, some of his criticisms are badly miscast. On various points, it's clear that Zimbalist is oblivious to most of the sabermetric progress of the past thirty years or so.

Take clutch hitting, for example, the subject that has arguably been debated the most of any controversy in the field. It seems like Zimbalist has seen none of that work. When Bradbury argues that clutch hitting talent is an illusion, Zimbalist responds

"There you have it – there is no such thing as clutch hitting. This is an awfully linear, materialist view of the world where a player’s emotions and his state of physical depletion over a 162-game season play no role."

This kind of intuitivist, naive response is what you expect from sportswriters, not from people who study sports economics for a living. But Zimbalist seems unaware of any of the body of literature on this question.

Here's another one. Bradbury talks about OPS, and how a better version of the formula would give more weight to OBP, perhaps by a factor of 3 (as Michael Lewis quotes Paul DePodesta in Moneyball). Zimbalist writes,

"... SLG ... is a much higher number than OBP. The coefficient, therefore, will necessarily be smaller on SLG. If elasticity is used instead of the estimated coefficient, OBP is 1.8 times greater than SLG."

Here, Zimbalist is trying to criticize Bradbury for the way he casts the question, arguing that the coefficient is an inappropriate measurement here. But if he were familiar with Moneyball, or the debate on OPS, he'd have known that the question DOES refer to the coefficients, and, yes, we are indeed aware that SLG is a higher number. Again, it's apparent from his comments that he has no idea there's already an extensive literature on the subject.

And here's one more:

"[Bradbury argues] that a pitcher’s ERA from one year to the next is highly variable, but that a pitcher’s walks, strikes and home runs allowed are more stable over time. The inference is that ERA depends more on outside factors, such as a team’s fielding prowess, and, hence, is a poor measure of the inherent skills of a pitcher. While there is something compelling to this logic, it seems caution is in order. First, a pitcher’s skills may actually vary from year to year, along with his ERA, as other factors change, such as, his ballpark, his pitching coach, his bullpen, his team’s offense, the angle of his arm slot, his confidence level, etc. This variability does not mean that the skill is spurious. Second, if all we consider is strikeouts, walks and home runs, what are we saying about sinkerball pitchers who induce groundballs or pitchers who throw fastballs with movement or offspeed pitches that induce weak swings and popups?"

That last sentence, about pitchers inducing weaker balls in play ... well, what we are saying about it is the DIPS theory. And that chapter of Bradbury's book does include an extensive discussion on DIPS ... if Zimbalist did indeed read it, you can't tell by his argument here. Bradbury rips into Zimbalist for this, with a lot more restraint than I would. Also – and this Bradbury does not mention – is that it's not just "outside factors such as a team's fielding prowess" that makes ERA unreliable. It's mostly just luck – whether the hits, walks, and home runs are bunched together or not. I'm sure Bradbury, or any one of countless bloggers and writers in the field, could have told Zimbalist this.

Anyway, as I said, Bradbury defends himself against Zimbalist quite well. For my part, though, I have to say that it's disappointing that Zimbalist, who is so respected in the realm of sports economics, would know so little about sabermetrics. After all, sabermetrics is an established scientific discipline, and one quite substantially impacts his own. Moreover, Zimbalist seems unaware that he is unaware. You'd expect a reviewer to be well-versed in the subject he's reviewing, but that doesn't seem to be the case here.

Zimbalist's review has been published in the "Journal of Economic Literature," an academic publication. This is unfortunate. I don't know much about how things work in academia, but it does seem that Bradbury's reputation will take a unfair hit -- at least on these sabermetric points, on which Zimbalist's less-than-fully-informed criticisms are way off the mark.