I've long been a fan of John Hollinger, who writes about basketball for espn.com, in large part because of Hollinger's statistical system for analyzing NBA players. Hollinger calls it PERs, and I like it chiefly because I'm in favor of any system that tries to improve on what I think are our woefully inadequate intuitive judgments of basketball ability.
Berri's argument is quite simple. As those of you who have read "Wages of Wins" know, Berri's big problem with the way we judge pro basketball players is that we over-rate the importance of how many points a player scores, and vastly under-rate the importance of things like turnovers, rebounds, and shooting percentage.
Now comes Berri's critique of Hollinger: he says that Hollinger makes the same mistake. Here's the critical section:
In discussing the NBA Efficiency metric – which the NBA presents at its website – I argued that this measure fails to penalize inefficient shooting. The regression of wins on offensive and defensive efficiency reveals that shooting efficiency impacts outcomes in basketball. The ball does indeed have to go through the hoop for a team to be successful.
The same critique offered for NBA Efficiency also applies to Hollinger’s PERs, except the problem is even worse. Hollinger argues that each two point field goal made is worth about 1.65 points. A three point field goal made is worth 2.65 points. A missed field goal, though, costs a team 0.72 points.
Given these values, with a bit of math we can show that a player will break even on his two point field goal attempts if he hits on 30.4% of these shots. On three pointers the break-even point is 21.4%. If a player exceeds these thresholds, and virtually every NBA played does so with respect to two-point shots, the more he shoots the higher his value in PERs. So a player can be an inefficient scorer and simply inflate his value by taking a large number of shots.
I'd be interested to see how Hollinger replies to this.
As I recall from the last time I posted on Berri, some readers have a problem with Berri's conclusions, mostly because his system ends up highly valuing players like Ben Wallace and Dennis Rodman and Kevin Garnett and dismissing the value of players like Allen Iverson. But the more Berri's fleshes out in arguments, the more convinced I become.
If you're a skeptic, I urge you to start reading Berri's blog.
One more point: one of the fascinating things about this argument is how similar it is to the argument currently going on in medicine about "clinical" versus "acturial" decision-making. One study after another has demonstrated that in a number of critical diagnostic situations, the unaided judgment of most doctors is substantially inferior to a diagnosis made with the assistance of some kind of algorithm or decision-rule. Doctors don't like to admit this. But it happens to be true.
A lot of the huffing and puffing about Berri's ideas, it strikes me, is just basketball's version of the same defensiveness and close-mindedness.