Crashing the Boards: A First Look At SportVU Rebounding

Dec 19, 2014; Denver, CO, USA; Los Angeles Clippers center DeAndre Jordan (6) grabs a rebound during the first half against the Denver Nuggets at Pepsi Center. Mandatory Credit: Chris Humphreys-USA TODAY Sports

Now more than a third of the way through the season, we’ve still barely scratched the surface of what can be learned from the public SportVU data available on NBA.com. An overwhelming majority of the analysis has focused on shooting, whether examinig shot selection and defense[1. both myself and Krishna Narsu have come up with metrics which measure shot selection and shotmaking ability to a degree], or teasing out specific areas of defense.[2. Such as my rim protection estimates]. What hasn’t gotten nearly the attention has been rebounding. However, there is almost as much detailed SportVU rebounding data available as there is for shots taken.

Taking NBA rebounding leader DeAndre Jordan as an example, for every rebound he’s secured[3. barring any games the SportVU cameras may have missed, such as the Rockets/Timberwolves game from Mexico City earlier this season], there is a true wealth of information:

Everything from the shooter, the location of the shot, distance traveled by the rebound before secured, whether it was contested and by how many opponents can be seen. Much like with the shooting data, this can be sliced and diced in innumerable ways to start to tell us more interesting things about rebounding. Here’s just a few tidbits of what’s in there.

1. Conceding the offensive glass: Doc Rivers is somewhat notoriously for having his teams eschew offensive rebounding, instead preferring solid transition defense to the increased probability of offensive rebounds. The Clippers are 26th in OREB% this season after finishing 19th last season. Rivers’ last three Boston teams finished dead last in that category.[5. Source: Basketball-reference.com] The new data confirms this is a strategic move rather than simply lacking offensive rebounding talent . Through games of Monday, December 29, NBA teams contested rebounds on just under 43 percent of their own shots.[5. “Contesting” a rebound is defined as being within 3.5 feet of the rebound when it is secured, or roughly arms’ length]. The Clippers have by a decent margin the lowest rate of contesting their own misses:

However, when they DO choose to attack the glass, only Oklahoma City is more proficient than Los Angeles’ 54.9% rate of “winning” those battles. Whether this desire to get back on D with frequency is a wise tradeoff is an open question (though the four team which attack the offensive glass the hardest rank seventh, third, second and fourth respectively in most fastbreak points allowed per game[6. Per teamrankings.com].

2. More KnicksTape: Sometimes the ball just bounces funny and the defense isn’t in any possession to chase the rebound. 8.4 percent of all shots are rebounded by the offense unconstested. The only team currently allowing opponents to rebound more than 10 percent of its own misses uncontested? The Knicks:

3. Fundamentals: It’s an old coaching adage that defense isn’t over until you secure the rebound. The top team in the NBA in terms of winning battles on the defensive glass at 57.6 percent? San Antonio, who also allow the second fewest “free” offensive rebounds in the league.

4. Sticking His Nose In: A huge part of Golden State’s success has been their ability to play Draymond Green at the 4. While Green is undersized, his quickness and shooting ability is a matchup nightmare on the other end. Part of the reason Golden State can get away with playing “small” is Green’s ability to compete on the defensive glass, often a weakness of small ball lineups. Certainly opponents are trying to attack there with the Warriors second to last in terms of percentage of defensive rebound chances uncontested by the opponent. Still, they are only slightly below average in terms of securing the rebound, in part because of Green’s ability to outfight and out-hustle larger players for the ball. Among the 100 players with the most total defensive rebounds, Green is tied for 15th in terms of fighting off the most opponents for those boards, and 21st in terms of winning those battles . Other players high on these lists include the expected behemoths such as Kevin Love, Anthony Davis, DeMarcus Cousins and Dwight Howard.

This info is just scratching the surface of what’s available to be learned in terms of offensive rebound rates from various shot locations, which players appear to be adding value with their rebounds versus simply padding stats by gobbling up as many of the 57 percent or so of defensive rebounds which are uncontested, which players might help their team by getting more involved on the glass and so forth. Further research might be able to combined this information with play-by-play or other on/off data to investigate if certain players help or hinder a team in securing various types of rebounds, and so on. All that’s needed is more time and thought.