Basketball Prospectus: Unfiltered Everything Else is Fluff.

January 20, 2010

Seth Davis is right, and so am I

Filed under: Uncategorized — John Gasaway @ 1:17 am

When Seth Davis posted his latest installment of Hoop Thoughts at on Monday, I of course zeroed in on this:

I’m a little surprised that more details haven’t leaked out about the statement of facts the NCAA sent to Mississippi State last week about Renardo Sidney. From what I’m hearing, there are some extremely problematic allegations in that document. The school has the option of challenging those facts, but I think it’s safe to say that Mr. Sidney will not play a minute of college basketball.

I’m inexorably drawn to paragraphs suggesting that one of my reckless predictions from the previous decade may actually be proven correct. So I printed that passage verbatim on a t-shirt and went happily about my business.

Others, however, read the same series of Hoop Thoughts and came away with a different reaction:

C’mon, @SethDavisHoops. What did @JohnGasaway say about killing #unicornstat “rebound margin”?

Who, what, where? What’d I miss? Oh, right. Further up in that same piece by Davis…. 

The thing I most respect about Villanova is that even though they have small teams every year, they still do a great job on the boards. This season they have a +6.8 rebound margin, which is ranked fifth in the Big East. I also love that they get to the foul line so often instead of settling for threes.

After all ‘Nova did reach the Final Four last year in part because, as I put it at the time, they were “absolutely insane” on the defensive glass in the tournament. And no one can doubt that Jay Wright‘s team does indeed get to the line a lot.

Well, I certainly don’t see any need for further exegesis here. Nope, no harm, no foul….

What’s that? Davis said what about me?

He is wrong (for once). Coaches cite it all the time. RT @crashthedance: C’mon, What did @JohnGasaway say re #unicornstat “rebounding margin”?

Seth’s right to say that coaches use rebound margin all the time. They do. In fact he would have been even more right if the 140-character limit had given him room to say head coaches cite rebound margin all the time.

Then again the large majority of D-I coaching personnel are not as yet head coaches. These less well-established staff members are in my experience much more open to the idea that there’s a better way to measure how well their team is performing. For example this season I received the following query from a program that’s been to the Final Four in the past five years. Who knows, maybe their head coach would be appalled to learn that his staff was sending me a question like this:

Our coaching staff has been reading and researching quite a bit about some of the better statistical measures to evaluate our team’s performance as opposed to the standard per-game numbers. We are really interested in tracking our Offensive and Defensive Rebounding Percentage. The one question we have not been able to find an answer to is the “target” percentage we should aim for on each end.

A significant minority of these D-I staff members will become head coaches someday, and I recklessly predict that when they do “rebound margin,” while continuing to exist as a vaguely familiar sequence of syllables, will gradually fall into benign neglect as an actual vessel of analysis, about like a pitcher’s sheer number of wins in baseball. The neglect will be both strangely overdue and richly deserved: Rebound margin is a mess.

Take Villanova. The Wildcats’ rebound margin ranks eighth in the league in Big East play. ‘Nova has recorded 178 total rebounds in five conference games; their opponents, coincidentally, have the exact same number. I’m on the record as admitting I really don’t know what to make of a factoid like that, since pace, shooting accuracy, FG defense, and how many turnovers you commit and force will all influence a given team’s “rebound margin.” But if you want to look specifically at rebounding and nothing else, we know exactly how well Villanova’s doing. In Big East play Wright’s team is pulling down a pretty good 35 percent of their own misses (fifth in the league), but a not-as-good 63 percent of opponents’ misses (ninth). 

Again, Seth Davis is correct when he says that coaches cite rebound margin all the time. It’s a stat that’s been around forever and habits die hard. But with each passing season this is one habit that’s being kicked by more and more coaches, writers, and fans. Rightly so.   

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