Inside David Lee's Rebounding

David Lee remains a controversial figure among Warrior fans. Over the last two years, he's clearly grabbed hold of the Monta Ellis Most Controversial Warrior award, and the team's success in the playoffs with him on the bench certainly shone a harsh light on some of this limitations.

Some of the criticisms of him seem unfair (it's hard to argue that his defense is the problem, and then turn around and advocate smallball) but with his mysteriously vanishing jumpshot (he's shooting only 39% from 10-15 feet this year, despite getting assisted more often, compared to 48.5+% the last two years) and the improvement of Draymond Green, more and more the rumblings about his performance seem hard to ignore.

The team seeming to clearly play better with Draymond against Charlotte - a game the Warriors should have won easily - may be the final straw.  David Lee may be the weakest member of the dub's starting rotation, and he might not be better than his backup, despite being the Warriors' highest-paid player.

I've generally been positive about Lee's contributions in the past couple of years. I'm not a hater. That's a necessary context for what follows.

The SportsVU cameras that have been installed in every NBA arena allow teams to track individual data in ways we hadn't previously been able to explore. One of the things they measure is whether or not a rebound is "contested" - that is to say, was an opposing player within 3.5 feet.

This allows us to study, in greater depth, the question of Lee's rebounding. Lee has been a curious case, reboundingwise, over his career. He grabs a lot of rebounds, but his teams - be they good or bad rebounding teams - generally haven't rebounded better with him on the court. He's not great at boxing out. But using the SportsVU "contested rebounding" data I decided to look at what it had to say about David Lee.

Before we get to the nitty gritties, a few things about these numbers. These are per-game numbers, which means they're affected by minutes played per game. Also, this is new data, so we don't really know how consistent it will be from year to year.

The first thing I did was sort by contested rebound percentage, for all players who averaged 6.5 rebounds a game or more. The idea was to compare PFs, and while a few SFs (notably Rudy Gay and Luol Deng) slip into that dataset, it seemed like a reasonable comparison group.

According to the player tracking data on stats.nba.com as of 7:45pm on December 10th, there are 59 players who are averaging 6.5 rebounds per game or more in the NBA. I then removed the following players from the dataset because they are not big men: Luol Deng, Rudy Gay, Evan Turner, Kobe Bryant. I left Shawn Marion and Al_farouq Aminu, and Kevin Durant in because they do play some 4, although most people wouldn't call them big men. As you'll see, it's a judgement call that doesn't significantly affect the results.

This leaves us with a dataset of 55 players. The lowest contested rebounding percentage among this group is Kevin Durant (24%), which isn't surprising since he's not really a big man. He's followed by LeMarcus Aldridge (color me surprised) at 30.1%. The best player in this group was Jordan Hill at 48.8%. The median was either Kenneth Faried (39.7%) or Kevin Love (39.8%).

David Lee ranked 51st out of 55 players with a contested rebound percentage of 32%.

This is not the only way to slice the data, however. We could also look at the total number of contested rebounds pulled down by a player. Here Kevin Durant again brought up the bottom, with 2, followed by Josh Smith with 2.1. Andre Drummond led all players with 5.8. The median was 3.2, held by Carmelo Anthony, John Henson, and others.

Lee came in 38th, with 3 contested rebounds per game. (Unlike past years, his per-game numbers aren't inflated by a particularly high minutes count).

The impossible-to-escape conclusion of all this is that Lee significantly pads his rebound numbers with uncontested rebounds. He's a below-average rebounder who looks like a good rebounder thanks to his tendency to grab a lot of easy ones. Lee is 9th in the league at uncontested rebounds per game.

We can also see how a player does when looking at what percentage of the rebounds they are close to they get. Again, David Lee is near the bottom, getting only 56.3% of the rebounds he's within 3.5 feet of. This places him 43rd out of the 55 players in the dataset.

This should put the nail in the coffin of Lee being a good rebounder. He's not.

By the way, this data doesn't make Bogut look particularly good, either. He has a below-average 36.1% contested rebound percentage, and a slightly-above-average 3.3 contested rebounds per game. In other words, he makes up - barely - for being a slightly below average by-the-percentages rebounder by grabbing enough rebounds to make him a better than average rebounder overall. (Also recognize that directly comparing Lee and Bogut's total rebounds is misleading because Lee plays more minutes than Bogut. The gap is bigger than those numbers make it look - Bogut is still a good rebounder. Lee isn't).

Interestingly, some the league's surprise results so far can be explained by this data:  For example: Hill and Robin Lopez are leading teams which are, to many eyes overperforming: they're among the league leaders in contested rebound percentage, and both over 4 contested rebounds per game.

Andre Drummond (44.5% contested rebound percentage, 5.8 contested rebounds per game) and Anthony Davis (46.3%, 4.7) both look good by this data, as well, as does Omer Asik (46.1%, 3.1 in only 18.5 minutes per game), while Dwight Howard looks mediocre, leading the league in uncontested rebounds per game, and only getting 32.3% contested.

We now have a statistically justified explanation for the discrepancy between Lee's individual rebounding and his impact on his team's rebounding. Now it's going to be up to the coaches to figure out how to do something about it, or Bob Myers to pull more magic out of his hat.