Party Crashers: Debunking the Myths of Offensive Rebounding and Transition Defense
There has been a sense of pessimism and fragility around the Indiana Pacers during their rise from bug-eyed no. 8 seed to bona fide contender — a feeling around the league that they’d gotten a little bit lucky in some way, and that the fates would turn against them next year. Before last season, the anxiety surrounded their health; they’d been perhaps the “healthiest” team in 2011-12, and the injury gods would surely strike them soon. The Danny Granger news broke early, but the Pacers still came within five wins of the championship.
Last year’s playoff run has solidified Indiana’s place in the league’s upper echelon, and the presence of stable bench cogs in Granger (or Lance Stephenson), C.J. Watson, and Luis Scola should allow Pacers fans to watch backups without getting the shakes. But a few eagle-eyed team execs have pointed to something Indiana pulled off last season and said, essentially, “No way they can do that again! And how good can they really be if they don’t do that again?”
What that is: The Pacers were perhaps the league’s best offensive rebounding team — no. 4 in offensive rebounding rate during the regular season, no. 1 by a long shot in the playoffs — and the stingiest transition defense in the league by almost every available measure. There’s a fairly widespread assumption that it’s very hard to be good at both of these things. Crash the offensive glass aggressively enough to earn a meaningful number of extra possessions, and you’ll stab at your own transition defense. That follows in part from the belief among coaches and (some) stats-oriented front-office people that offensive rebounding doesn’t really matter in the construction of winning teams.
Doc Rivers has been perhaps the loudest coach in proclaiming the irrelevancy of the offensive glass:
“So, you’re a big believer in offensive rebounds I think; I’m not. Listen, like I said, you can pick on that all I want. That is a number I rarely look at, is offensive rebounds. Statistically it holds up. I can tell you, you don’t offensive rebound, you stop transition, you win more games than when you get offensive rebounds. I can guarantee you that on those stats.”
But he’s far from the only one. The Spurs under Gregg Popovich have long punted on offensive rebounding out of the same belief, and several of the most successful teams in recent NBA history — Rivers’s Celtics, Stan Van Gundy’s Magic, Mike Brown’s Cavaliers (to a lesser extent), the current Miami Heat — have been happy at the bottom of the league’s offensive rebounding ranks. League-wide, offensive rebounding rate has been on a prolonged drop. “As a coach, you look at what is most important to winning and construct a game plan around that,” says Jeff Van Gundy. “And offensive rebounding just doesn’t seem to have a correlation with winning big.”
There are two connected assumptions here:
1. Crashing the boards means sacrificing transition defense.
2. Offensive rebounding doesn’t really matter.
The Pacers are basically spitting in the faces of both of those assumptions. And in doing so, they are hinting at a burbling reconsideration around the league of the relative importance of offensive rebounding in general. “We understand it’s extremely difficult to be good at both,” says Frank Vogel, the Pacers’ head coach. “But I think you have to try to be good at both. There are a lot of opportunities to explore.”
Indiana last season allowed exactly 10 fast-break points per game, the lowest figure in the league in five years, per NBA.com. The stat-tracking service Synergy Sports classified about 11.5 percent of Pacers opponent possessions as “transition” chances — also the lowest mark in the league. The Pacers allowed just 1.03 points per possession on those transition chances. Guess where that mark ranked league-wide?
Oh, you prefer the transition-points-allowed numbers at Team Rankings, which uses its own formula? The Pacers blew the league away by that standard, too.
Several front-office people who have studied the issue have found very little correlation between offensive rebounding and transition defense. Last year’s elite offensive rebounding teams also included the Grizzlies and Nuggets, both of whom fared very well in containing transition attacks, per all the tracking sources mentioned above. To examine this, I looked at the top five offensive rebounding teams in each of the last five seasons — so 25 teams total — to see how they ranked in various measures of transition defense. Here are the average rankings of those 25 teams in the key available metrics:
• Fast-break points allowed, per NBA.com: no. 13
• Synergy points allowed per possession on transition chances: no. 13
• Percentage of opponent possessions Synergy classified as transition chances (i.e., a rough measure of how often opponents got out on the break): no. 17
• Points allowed per possession on transition chances via Team Rankings: no. 16
This is an imperfect exercise, obviously. Everyone has their own way of calculating fast-break points. The NBA’s method, for instance, focuses on time remaining on the shot clock when a team scores — a threshold that discounts a lot of secondary transition hoops. Teams have their own internal metrics. No single number is perfect, and teams keep their own numbers secret.
But the available numbers suggest elite offensive rebounding teams fare just about like anyone else in transition defense. They’re average overall. Some are really good, and some — hi, DeMarcus Cousins! — are terrible. But there’s no obvious evidence that crashing the offensive boards is a death sentence for a team’s transition defense.
The Pacers obviously aren’t worried. When Brian Shaw left to coach the Nuggets, Indiana hired Nate McMillan to work as Vogel’s lead assistant. McMillan’s Portland teams were the proto-Pacers — monsters on the offensive glass and in fast-break prevention. Both coaches have strict rules in place designed to ensure three players chase after every miss, they say.
If both big men are in the paint, Vogel expects them to pursue offensive rebounds. The third player will be a wing, typically the guy hanging out on the weak side along the baseline, Vogel says. Paul George has the size to be a solid offensive rebounder, and Stephenson brings a desirable combination of athleticism, anticipation, and a lunatic willingness to toss his body around. (Note: This hasn’t yet resulted in either player recording above-average offensive rebounding rates for their position, but Vogel is confident that could change.) The other wing has to scramble back immediately upon the release of a Pacers shot, Vogel says. George Hill does the same, unless a given set play has him positioned along the baseline.
There are sub-rules. If David West shoots a 20-footer on the pick-and-pop, he’s supposed to get back on defense instead of chasing his miss; a second wing is then allowed to take West’s spot in the crashing hierarchy. And there are techniques, McMillan says. Modern NBA offenses often space the floor by having a shooter in each corner, and under the Vogel-McMillan system, one of those guys is supposed to hit the glass. But that player cannot just take a straight-line path along the baseline, McMillan says. Instead, he should loop from the corner up toward the foul line when a teammate shoots, and once along that path, decide midway whether he’s got a shot at the offensive board.
Following that curl pattern ensures the player will have already started retreating back on defense in case the rebound goes elsewhere, or if the player concludes he has no chance at it, McMillan says. Scrambling along the baseline would leave that player way behind the action.
Vogel and McMillan have rarely altered these principles, not even against LeBron’s Heat or the Steve Nash–era Seven Seconds or Less Suns. Both believe having more players crashing the offensive glass might actually make their team’s transition defense better. If opponents know the Pacers are going to chase boards like maniacs, those opponents can’t start leaking out for fast breaks, the coaches say. “We always felt like if we were putting pressure on opponents to box us out,” McMillan recalls, “then they couldn’t get out and run.”
It’s tempting to look at all this and suggest coaches are leaving points on the table out of caution. That was essentially the conclusion of several MIT students who used camera-tracking data to see (among other things) how often teams had two, three, or even four players crash the offensive glass — and what happened as teams sent an extra body or two to the boards. The general conclusion the authors presented at the MIT Sloan Sports Analytics Conference in March, based on data from the 2011-12 season, was that teams could net about four extra points per game by recalibrating their philosophy toward offensive rebounding — that teams were being too cautious.
The authors have since looked at data from the 2012-13 season and found the same effect, says Jenna Wiens, the lead author and a PhD candidate at MIT. (She also once played water polo, meaning she is automatically cool.) And as a fun aside, Wiens and her team found two teams changed their offensive rebounding philosophies dramatically between 2011-12 and last season: Minnesota and Washington. The Wolves appear to have sent an extra player, on average, to chase offensive boards, while the Wiz focused more on transition defense, Wiens says.
The Wolves nugget speaks to the importance of personnel. In 2011-12, they had Kevin Love, one of the world’s great offensive rebounders. Love missed most of last season, and the team shot a pathetic 30.5 percent on 3-pointers. When you have Kevin Love, you can sustain on the offensive glass without over-pursuing. When you don’t have Kevin Love, you might need to send an extra player, especially when you know you are a horrible shooting team that needs extra chances to survive.
Perhaps this is really about team personnel more than anything else. The Pacers have Roy Hibbert, who grabbed 14.8 percent of Indiana’s misses last season — second in the league only to Reggie Evans in individual offensive rebounding rate. The Grizz have Zach Randolph, no. 4 in that category, and one of the greatest offensive rebounding bullies ever. Denver started Kosta Koufos and Kenneth Faried, nos. 5 and 6 last season in offensive rebounding rate, respectively. Those McMillan-era Blazers featured small doses of Greg Oden, heavy doses of Marcus Camby (who was doing the Tyson Chandler tip-out before Chandler made it cool), and lots of Nicolas Batum executing that curl pattern very well, McMillan says. If you have big guys like this, maybe it’s just a lot easier to do well on the offensive glass without asking a third player to contribute.
On the flip side: The Spurs and Celtics, the most visible punters of offensive rebounding, have leaned on two all-time great aging bigs — Kevin Garnett and Tim Duncan. Big men tend to slide away from the hoop as they age, and both Garnett and Duncan have followed that pattern, deemphasizing the offensive glass in their golden years. The Van Gundy Magic had Dwight Howard, an elite offensive rebounder, but they also played smaller lineups with Rashard Lewis at power forward and stressed the importance of stationing four guys behind the 3-point arc.
And that’s something that might be behind the long-term decline in offensive rebounding — spacing, and the emphasis on the 3-point shot, and especially the short corner 3. If a team has all three perimeter players out there, including two in the corners, they’ve got a long way to go to get into rebounding range, and taking a few false steps toward the rim could affect transition defense. And if you’ve got a stretch power forward — Dirk Nowitzki, Ryan Anderson, etc. — forget about it. Personnel drives spacing, and the emphasis on spacing has taken guys away from the basket. “Teams now rely on spacing so much,” McMillan says. “And you see it all the time, teams whose spacing is such that when a shot goes up, they don’t even have one person going to the boards. They are just conceding the offensive glass.”
There is a growing sense that teams have gone too far in offensive rebounding paranoia. Jeff Van Gundy wonders if this is especially true in the playoffs, when the pace slows, teams face the very best defenses, and points become more scarce. “You have to ask yourself: In the playoffs, is offensive rebounding more important?” Van Gundy says. “Because scoring is harder. And so, should we construct an offensive rebounding identity early, so that we have another weapon in the playoffs?”
And yet, the correlation between offensive rebounding and winning is still very low, according to several stats experts around the league. Is there a chicken-and-egg thing going on there? Or does offensive rebounding really not matter, as Van Gundy and other coaches have found in the historical data? After all, we’re talking about only a handful of possessions each game. Teams snag only 11 offensive rebounds per game on average, and not all of those lead to baskets or free throws. Would jacking that number up to 14 or 15 really make a difference, especially considering that the very existence of an offensive rebounding chance flows from a negative event — a miss? Maybe teams who are “good” at offensive rebounding are good because they miss a lot — because they are bad at offense.
No one is sure, not in a league where the difference between winning and losing could be a couple of bad bounces. But the idea that good offensive rebounding and good transition defense are mutually exclusive appears to be a myth. Heck, even the Spurs allowed Kawhi Leonard some freedom to crash the offensive boards in the Finals by lurking along the baseline instead of chilling in the corner — and against the Heat, a terrifying fast-break team when enabled.
This is a topic teams are thinking very, very hard about. The truth is still out there. But the Pacers? They know who they are.