How good a marginal rebounder are you really?

Maybe this is too strange and squirrelly an example to deserve mention on MR, but I found it fascinating.  It starts with this:

This year’s rebounding leaderboard, at least in terms of rebounds per game, is topped by DeAndre Jordan and Andre Drummond, who also finished 1-2 last season. In a bygone era, you’d simply say they are the league’s best rebounders at this time. Yet it might not be that way at all.

There seems to be a huge oops:

Both the Clippers and Pistons have better defensive rebound rates with their star rebounders on the bench. How is that possible?

This is a big topic, but one possible reason could be the simple fact that neither Jordan nor Drummond is particularly concerned with boxing out…Drummond blocks out on the defensive glass just 5.97 times per 100 opportunities, lowest in the league among centers with at least 500 chances.

Jordan is a little better at 9.64, but that’s still the 11th-lowest total.

In other words, what really matters is marginal rebounding prowess, adjusting for how many rebounds you take away from the other players on your team.  Maybe an individual can pull in the ball more often by positioning himself to grab the low hanging fruit rebounds — often taking them from other team members — rather than boxing out the other team for the tough, contested rebounds.

Measurement really is changing the world.  The article is here, by Bradford Doolittle, ESPN gated.  Here is more on DeAndre Jordan, also ESPN gated.  That is one media source I pay for gladly.


So many coaches, for so many years, paid to propagate so much ignorance. Coaches in,our intro stats classes were always used as the classic examples of folks who seldom understand simple concepts likeregression to the mean.

'Measurement really is changing the world'

Well, to the extent measurement is acccurate, it isn't changing the world at all, merely reflecting it. Our perception of the world may be changed by measurement - the world, not at all.

Only if you could not learn from, and react to, this better information. For you, this is probably true.

I'd call it "team-rebound product" or "team-rebound productivity."

Very interesting. Would be interesting to hear who most boosted their teams' rebounding rates. Got to imagine Barkley and Rodman, neither of whom were all that tall.

The margin could esily cut the other way (numbers out of nowhere). If a top rebounder grabs a high enough % by himself then additional players crashing won't improve much. If Jordan had a 30% d reb rate on his own and Jordan + Griffin went to 40%- you might be better off having Griffin less aggressive on the glass if it turned into fast break points, or mismatches on the other end of the court. Lets say that then Hawes comes in for Jordan and he has a 25% rate and Hawes+Griffin has a 38% rate. You have a greater return on Griffin's rebounding when Hawes is in so he should be more willing to sacrifice in transition.
Early this season the Cavs were experimenting with a unique setup. Love was killing the D reb with almost no O reb (especially for him) and Tristan Thompson was killing the offensive glass with terrible defensive numbers- meanwhile the Cavs were #1 in pace adjusted transition points (iirc) despite being an average D reb and avg to below average steal generating team.

Don't subscribe to ESPN, so I couldn't read the article. Both Jordan and Drummond are league leaders in blocked shots.
That means their defensive responsibility on any perimeter penetration is to "guard the paint," contest any drives, and alter or block any shot attempts. It's that defensive "help," which takes them out of position for defensive rebounds. Whether the reporter took that into account, I don't know.

In high school basketball, almost 70% of missed shots are going to the weak side. The next most likely other destination of a miss is right back at the shooter. In the NBA players have long been required to memorize all the plays of all the teams they play against. I'm guessing they chart misses by player. Meaning when player X shoots, the defense is supposed to know where X's misses usually go. I'm guessing in the NBA that the defensive rebounding "decision tree" starts with "can I get the rebound before anyone else?" If that's the case, you don't box out, you go after the rebound.

IIRC, Hank Iba didn't teach his players to box out. There's been a long-running argument among coaches on this topic.

IMHO, especially at the grade school and high school level, boxing out is good fundamentals and the way to go. If you have better athletes, however, it's understandable that coaches at least consider leveraging that advantage and just let them go to the ball.

Ah, you beat me to it.

It would be interesting if this metric could go back and see how top rebounders of the past -- Wilt and Rodman -- would fare on this. I'm too young to remember Wilt with any clarity, but I would guess Rodman would do well.

Of course, Rodman could pretty much concentrate only on rebounding -- there's only one ball, and Michael and Scottie were happy to handle it.

I believe you mean Isiah and Joe.

Rodman blocked out as well as any player I ever watched play the game.

Could be. OTOH, Rodman was notorious for grabbing some rebounds which did not help his team at the margin, namely defensive rebounds after opponents' missed free throws. The defenders almost always get the defensive rebound anyway, they don't need to have a Wilt or Rodman there. Moreover there are two of them who are ideally located to grab the defensive rebound -- and Rodman when he was with the Bulls insisted that he always be the one who grabbed them, to pad his rebounding statistics. More rebounding stats for Rodman, but no marginal rebounds for the Bulls, because they would've grabbed the defensive rebound anyway.

So how many angels can dance on the head of a pin?

ouch . Rather cynical, but yeah... sports is much like religion -- a widely popular form of distraction, entertainment, impressive time and money waster, social conflict generator, and ready anesthesia from life's daily grind. Alcohol use has a similar profile.

Distraction from what? Nothing in human affairs is important.

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You know what there never seems to be much critical analysis of? Sports statistics. Why is it that when visionaries like Dean Oliver or Billy Beane succeed, it's science, but when they fail it's magic (by that I mean bad luck).

Maybe these brilliant new measures mean less than people like Tyler believe they do.

You have to account for something else here- what are the other defensive duties of the players in question? I know for a fact that Drummond is a shot blocker. You can't box out if you are contesting the shot itself. I would be more interested if these stats are broken down by where the shot was taken- was it taken in the paint, or was it taken from well outside the lane.

Hibbert is a shotblocker/rim protector, and he boxes out. Duncan is the same and boxes out pretty well usually. The big difference is that guys like Drummond and Jordan leave their feet a lot, even for shots outside the paint. Smarter defenders, like Duncan, stay on their feet and go for the block around the rim more often. That's generally more valuable. The problem with leaving your feet a lot is that you're out of position on defense and for the rebound.

The real interesting thing in this post is the fact that Tyler would 'gladly' pay for ESPN content, which implies that they could (will soon! ) charge him more. I'm of the opinion that most of the valuable internet content will eventually be behind a pay wall. I would be interested in a post on what else Tyler would gladly pay for whether it currently has a fee or not.

On topic, the analysis seems to ignore player rotation as well. It is likely that opposing teams match their 2nd team up with each other. So, the Clippers' and Pistons' 2nd teams are better rebounders than opposition 2nd teams.

Careful in interpreting SportsVU stats.

When Dwight Howard went down, people were raving over his replacement's (Donatas Motiejunas) ability to play "just as good defense" in the paint.

According to SportsVU, opponents shot a lower percebtage in the paint against DMo than against Dwight.

Later though, a different stat showed that teams most of the time dont even TRY to shoot in the paint vs Dwight. He completely shuts the paint down, not even letting anyone inside in the first place. The higher percentage was due to something else, small sample size or scheme or whatever.

Also, teams adjusted to DMo's style of defense (he moves well on his feet but has very little explosiveness to challenge shots) and he has begun struggle.

My guess is there's more to the story of the Clippers on/off rebounding.

Gee, if only someone had thought of this before. Oh, wait:

Step 2 literally says "Adjust for teammate’s production of defensive rebounds"


That does not adjust for what is being talked about here. Read both more closely.


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