Reining in the Moneyball Revolution’s Chief Excess, Twenty Years Later

What was the point of Moneyball? Nerds said on-base percentage is better than batting average and were technically correct on that narrow point? The real answer, of course, is that cheap owners‘ teams still can win by excelling at identifying and exploiting budget-friendly market inefficiencies. But when Brad Pitt says “on-base percentage is all we’re looking at now,” people tend to focus on that part and forget the rest.

Reaching base, however a player does it, is good, and counting only some ways players reach base necessarily misses relevant data points. By including walks and hits-by-pitch (“hit-by-pitches”?), on-base percentage (“OBP”) does paint a more complete picture of a baseball player’s offensive production than does batting average (“BA”), which only counts hits. The responsive inclination to look first to OBP rather than the traditional go-to, BA, thus is understandable.

Those comfortable with taking this new step, especially the early OBP adopters, often did so zealously and callously, even as they cloaked themselves in the mantle of measured reason. And when they did so, they very often took a second step: banishment of BA. Elevation of OBP was not enough; BA, the very embodiment of the old and impure way of thinking, must be cast out.

For the SABR revolutionaries, like not a few revolutionaries before them and to mix corporeal metaphors, that second step proved to be something of an overreach. As it turns out, the ancients were in fact onto something with BA, and there was something in that something that deserved to be conserved and carried forward through the revolutionary wave. BA, Eli Ben-Porat writes, not only deserves its place in baseball’s basic offensive statistic trinity– the Triple Slash Line of BA/OBP/SLG– but is the only component that actually belongs there.

As Ben-Porat explained over the weekend: “Dismissing batting average, in this author’s view, is just plain wrong. It is statistically significant in terms of predicting team runs, and on a per point basis, the most impactful component of” the building blocks of the triple slash line. After all, BA is a big part of both OBP and slugging percentage (“SLG”). And because of the way OBP weighs walks relative to hits, it can obscure the value of the offensive production it presents; in other words, not all OBPs are created equal. To Billy Beane’s point, it is important to account for a batter’s walks, but a hit– even a single– is better than a walk. Two players thus could post identical OBPs but have gotten there in much different fashion. Dumping BA would mask the real significance of a light-hitting, ball-taking batter’s empty OBP that matched the same mark of a more balanced player who hit more than he walked. Ben-Porat shows both that BA still matters and that presenting OBP without BA really makes the former less useful.

Whether Ben-Porat’s proposed adoption of an even more elemental triple slash line that omits the BA components of OBP and SLG and leaves the remainders (i.e., BA/BB%/ISO) catches on is another question. For now, rest with the satisfaction that you aren’t wrong to not get irritated when you see a player’s BA displayed during an upcoming MLB telecast.


Why I’m not going to see Moneyball
Baseball Notes: Offensive Discrimination
Window Shopping: Ian Kinsler’s Walking, Not Running
Trout vs. Cabrera, and Aging with DRC+