NBA 75: Hollinger: Who was the greatest rebounder ever? And how can we tell?
John Hollinger
14–18 Minuten
Who is the greatest
NBA rebounder of all time?
I used to think I knew the answer to this question because the data we had made it seem obvious.
Then we got better data.
Such is often the story of scientific inquiry, and it certainly has been in my case. In my 2002 edition of Pro Basketball Forecast, I asked the question “who is the greatest rebounder of all time,” and lead my readers through what that time was a cutting-edge debate about a new stat called Rebound Rate. Since you can only rebound a shot if somebody missed it, my logic seemed ironclad. Compared to today’s tools, however, my cutting-edge equipment was a sundial and a chariot.
We know a lot more now about how to measure impact than we did 20 years ago (or, really, five years ago), and what we know is that looking at one individual player is necessary but not sufficient to evaluate their wider contribution.
For one perfect example related to rebounding, we need only look at
Andre Drummond. By my statistical method of 2002, he certainly would rank as one of the top rebounders in history. Drummond led the league in Rebound Rate four times and leads it again this year. For the years where we have Rebound Rate calculations, Drummond’s 24.6 percent career mark is the highest of all time.
All time!
Andre Drummond!
Andre Drummond gets boards. (Jesse D. Garrabrant / NBAE via Getty Images)
It turns out, however, that there are other variables at play here that complicate things.
For instance, rebounding is much more unevenly distributed than it used to be. You can blame the 3-point line for that; it turns out it’s hard to rebound in quantity when you’re consistently 23 feet from the basket, which means centers — and, in particular,
unskilled centers — have had a greater share left to themselves.
We can see that in the data: The league leader in Rebound Rate has had a mark of 25.0 or above every year since 2015-16, with six players hitting the mark. That wasn’t always the case; boards were more distributed across the roster because more players were hitting the glass. In 1988-89, for instance, Robert Parish led the league in Rebound rate with a mark of 20.1; that would have placed him ninth in 2019-20. The Andre Drummonds of yore are working at a five-point disadvantage.
That’s not the only thing that has changed. Teams as a whole are much less aggressive going to the offensive boards, with the result that Offensive Rebound Rates have steadily declined. Offensive teams collected 32.3 percent of their missed shots in 1990; by 2021 that was 22.2 percent. The nature of the beast is different.
Finally, we’ve gotten better at measuring rebound difficulty. The sight of
Russell Westbrook padding his triple-double numbers by swooping in to grab every single missed free throw has made us realize that not all rebounds are equal. Stats like “contested rebounds” give us more context to what’s happening, and distinguishes between players hoovering up defensive boards on missed free throws and those winning genuine 50-50 balls.
More perniciously, we can go back to the question of “Are we even measuring the right thing here?” Rebound Rate is nice, but isn’t the ultimate goal to make sure your team gets the rebound, and not you individually? And so isn’t the thing we care about what happens to a team’s Rebound Rate when an individual player is added or subtracted to the equation?
Enter Drummond, for instance. He has some of the highest Rebound Rates in league annals, leading the league in that category those four times. He’s been an equal-opportunity glass-eater too, posting the highest Offensive Rebound Rate three times and the highest Defensive Rebound Rate four times. (Some players are dramatically better at one end than at the other.)
And yet … go back and look at Drummond’s “best” rebounding seasons. In 2016-17
Detroit got 51.2% of the rebounds available when Drummond played … and 53.0% of them when he didn’t.
While that season is an outlier, the overall pattern of his career isn’t entirely dissimilar. Drummond had a few seasons where he massively impacted the Pistons’ overall rebounding, but also at least three where his impact was more subdued.
Andre Drummond on-off Rebound Rate
Year | On | Off | Diff | RR Rank |
---|
2013-14 | 52.3 | 48.8 | 3.5 | 1 |
2014-15 | 50.8 | 49.9 | 0.9 | 2 |
2015-16 | 52.3 | 51.8 | 0.5 | 1 |
2016-17 | 51.2 | 53 | -1.8 | 1 |
2017-18 | 50.6 | 48.4 | 2.2 | 2 |
2018-19 | 51.7 | 49.4 | 2.3 | 2 |
2019-20 | 50.3 | 48.5 | 1.8 | 1 |
If he’s so good at rebounding — finishing first or second in Rebound Rate for seven straight years! — why isn’t his impact on the team’s rebounding not more profound?
Unfortunately, the NBA only has this data going back to 2007-08, so we can’t use it to make historical comparisons. But we can improvise a few while we’re here, to look at impact another way. Before we do that, let’s look at a few of Drummond’s contemporaries.
Year | On | Off | Diff | Reb Rate |
---|
2014-15 | 52.7 | 52.0 | 0.7 | 20.7 |
2015-16 | 52.4 | 51.0 | 1.4 | 20.2 |
2016-17 | 52.3 | 49.4 | 2.9 | 21.8 |
2017-18 | 52.3 | 49.7 | 2.6 | 18.8 |
2018-19 | 52.4 | 51.8 | 0.6 | 21.9 |
2019-20 | 51.5 | 50.4 | 1.1 | 21.6 |
2020-21 | 53.7 | 51.5 | 2.2 | 23.3 |
Year | On | Off | Diff | Reb Rate |
---|
2015-16 | 50.4 | 48.4 | 2.0 | 18.5 |
2016-17 | 50.9 | 49.3 | 1.6 | 18.5 |
2017-18 | 51.2 | 49.3 | 1.9 | 22.2 |
2018-19 | 49.5 | 46.3 | 3.2 | 20.8 |
2019-20 | 50.6 | 47.9 | 2.7 | 22.0 |
2020-21 | 53.4 | 49.4 | 4.0 | 26.1 |
Prime Dwight Howard on-off Rebound Rate
Year | On | Off | Diff | Reb Rate |
---|
2007-08 | 50.5 | 48.6 | 1.9 | 21.7 |
2008-09 | 50.8 | 48.9 | 1.9 | 21.8 |
2009-10 | 51.4 | 50.7 | 0.7 | 22.0 |
2010-11 | 52.3 | 50.3 | 2.0 | 21.8 |
2011-12 | 51.8 | 49.3 | 2.5 | 21.9 |
Hassan Whiteside on-off Rebound Rate
Year | On | Off | Diff | Reb Rate |
---|
2014-15 | 51.8 | 47.4 | 4.4 | 25.4 |
2015-16 | 52.1 | 50.2 | 1.9 | 23.1 |
2016-17 | 51.5 | 47.2 | 4.3 | 24.0 |
2017-18 | 50.6 | 49.8 | 0.8 | 25.4 |
2018-19 | 53.1 | 49.2 | 3.9 | 25.9 |
2019-20 | 50.4 | 47.7 | 2.7 | 23.6 |
Hassan Whiteside?
Yes, Hassan Whiteside. He ranks just behind Drummond on the Rebound Rate leaderboard, and his impact on team rebounding seems to be much stronger; in particular, a couple of his
Miami teams were desperately bad without him (47.2 percent? Bleccch) and extremely competent once he played.
Nonetheless, it doesn’t seem like there’s a contemporary player who quite injects that same fear of rebound domination; perhaps partly because all the best bigs now play on the perimeter.
Joel Embiid (or
Kevin Love before him) c
ould wreck people on the offensive glass, but he also has to shoot 3-pointers.
So then … Rebound Rate overrates Drummond?
Maybe. Maybe not. You see, the on-off differential is a comparison between the player and whoever replaces him; thus, having a lame backup can make a player look much better in comparison. (“Sure, we stink when I play, but when doofus over here checks in we’re still 10 points worse.”) The
Rockets rebounding shriveled to nothing in 2018-19 and 2019-20 without Clint Capela, for instance, partly because they backed him up with a shrug emoji.
And then, what of the next question: A lot of the greatest rebounding teams didn’t succeed because of a single great rebounder at all. Wouldn’t a truly great rebounder show up on the list of greatest rebounding teams as well?
It doesn’t work out that way all the time. Our
Grizzlies in 2012-13, for instance, were one of the best rebounding teams in recent annals, pulling down 52.7 percent of missed shots. That was partly because our bigs were good on the glass, especially Zach Randolph … and also partly because our shooting guard rebounded like a power forward, giving us an automatic leg up.
Few players worked harder on the boards, on both ends of the floor, than the late, great Moses Malone. (Ken Regan / NBAE via Getty Images)
You’ll see a lot of examples like this, where roster construction determines a team’s Rebound Rate. For instance, the best rebounding team I could find was the 1994-95
Trail Blazers, an otherwise completely ordinary team that won 44 games and got swept in the first round of the playoffs but rebounded an absurd 55.3 percent of missed shots. In a related story, that team started 6-foot-10 Clifford Robinson at small forward and sometimes played 6-8 Harvey Grant next to him at shooting guard.
Call it basketball’s Dunning-Kruger effect, then. If we just look at Rebound Rate we think we know it all, and once we incorporate other information we become progressively less confident.
That matters when we look at historical rebounding numbers because we don’t have nearly as much data. My previous research on this topic, in the
2002 Pro Basketball Prospectus, yielded four players who were pretty clearly all-timers if you just focused on Rebound Rate. Notably; my methodology had to infer Rebound Rates for pre-1971 players but the answer it came up with of “Bill Russell and Wes Unseld” would likely not be disputed by their contemporaries.
Russell and Unseld, by my estimated method for pre-1971 Rebound Rate, had six of the top eight seasons between them:
Estimated Rebound Rates for pre-1971
Player | Year | Rebound Rate |
---|
Bill Russell | 1956-57 | 22.9 |
Wes Unseld | 1968-69 | 22.5 |
George Mikan | 1953-54 | 21.8 |
Bill Russell | 1963-64 | 21.6 |
Bill Russell | 1957-58 | 21.1 |
Wilt Chamberlain | 1968-69 | 20.9 |
Bill Russell | 1964-65 | 20.6 |
Wes Unseld | 1969-70 | 20.5 |
Source: 2002 Pro Basketball Prospectus
What about Wilt Chamberlain, the league’s all-time rebounder? His per-game totals were padded a bit by the fact he never, ever subbed out. In terms of Rebound Rate, he likely wasn’t quite on Russell’s level.
The interesting part here is that we have no new information since I first wrote this nearly two decades ago; the pre-1971 era remains a black box beyond some basic stats. Nonetheless, the fact that Unseld and Russell impacted winning on a massive level makes us more confident in hailing their board exploits; these guys weren’t stealing free-throw rebounds to pad their stats.
Nonetheless, we have two names left to discuss, still likely the two greatest rebounders ever in my newly humbled estimation: Dennis Rodman and Moses Malone, one famous for tapping rebounds to himself in the air, the other for doing the same off the glass.
Malone changed teams a few times, so looking at his impact on rebounding is particularly fascinating. We don’t have “on-off” data for his era but we do have “new team” data. Each change moved the needle profoundly, both for the team he went to and the team he left.
Mose Malone change in team rebounding
Year | Moses Year | Post-Moses | Diff |
---|
1982-83 (Hou) | 51.9 | 48.1 | 3.8 |
1986-87 (Phi) | 52.0 | 50.3 | 1.7 |
Year | Pre-Moses | Moses Year | Diff |
---|
1976-77 (Hou) | 50.1 | 53.0 | 2.9 |
1982-83 (Phi) | 47.7 | 51.9 | 4.2 |
Malone’s body of work in other respects, of course, requires no introduction. He led the league in Offensive Rebound Rate eight times and overall Rebound Rate four times; surely he was the most feared rebounder of the post-merger era. I’m just young enough to have seen him play and witnessed the carnage first hand, most notably in the 1981 Finals — when he played against one of the great frontcourts in history and had 46 offensive rebounds in six games.
You can do the same exercise for Rodman and his major team changes:
Dennis Rodman change in team rebounding
Year | Rodman Year | Post-Rodman | Diff |
---|
1992-93 (Det) | 51.7 | 51.2 | 0.5 |
1994-95 (SA) | 51.6 | 48.7 | 3.9 |
1998-99 (Chi) | 53.2 | 49.3 | 3.9 |
Year | Pre-Rodman | Rodman Year | Diff |
---|
1993-94 (SA) | 48.9 | 53.0 | 4.1 |
1995-96 (Chi) | 50.6 | 54.0 | 3.4 |
This is where things get crazy. You’ve seen all the numbers for all the other great rebounders in history in the tables above, and then Rodman’s data comes up, and it’s from a completely different planet.
Rodman led the league in Rebound Rate in eight consecutive seasons, from 1990-91 to 1997-98, and his team-wide impact was just as clear — the 1995-96
Bulls, for instance, had the second-best offensive rebound rate in history and one of the best rebound differentials. Everyone remembers him with the Bulls and Pistons, but the San Antonio stretch is arguably the most impressive part. He spent two years in San Antonio; the
Spurs were a crap rebounding team before he arrived and after he left, but in the middle were among the league’s best, with Rodman setting a still-standing record for Rebound Rate despite playing in an era where high Rebound Rates weren’t a thing.
As a result, Rodman didn’t just lead the league in Rebound Rate during his prime seasons, he led it by absolutely absurd margins. In 1994-95 his Rebound Rate of 29.7 was the highest for any season we have data, and given the historical trend line it was a truly Ruthian feat; no other player was above 20 that season. Rodman’s rate was nearly 50 percent higher than the closes competitor,
Cleveland’s Tyrone Hill, who clocked in at 19.9. By the way, he did this while playing next to David Robinson; since rebounding is a zero-sum game, the Admiral surely cut into his total a bit.
Rodman posting a 26.6 Rebound Rate – the highest in history, except for his mark the year before in San Antonio – while playing for the best team ever is a pretty strong prima facie case that he was rebounding in ways that were actually helping the team and not just hoarding boards for his stat sheet. (Although, certainly, he was guilty of this too.) Those Bulls were also an elite rebounding team overall.
At only 6-7 but with perhaps the quickest second jump in history and a single-minded focus on rebounding, Rodman was unquestionably the best at tapping rebounds to himself and then grabbing it on his second, third, or even fourth jump. He also became a regular practitioner of offensive rebound tap-outs later in his career, something Tyson Chandler later turned into an art form.
So, who is the greatest rebounder ever? I would humbly submit that I feel less confident in this answer than I did two decades ago because the data will never be clean enough for us to answer this question with totality.
However, we can take the data we do have, along with the eye test and historical accounts, and piece together an ad hoc list of the greatest rebounders ever. We’ll never have enough information to know where to rank Russell relative to Moses Malone, but we have some pretty decent data indicating those two are probably head and shoulders above every player not named Dennis.
It gets harder if we’re trying to turn our rebounding holy trinity into a Mount Rushmore. Reasonable people can argue over whether Unseld or perhaps another player from the post-merger era belongs. Nobody from the current era is quite on that level, it would seem, although Hassan Whiteside has a stronger case than you might expect.
And at the top
, the unquestioned George Washington of that mountain would be Rodman. All the data we now have at our fingertips still supports the basic conclusion that his board work from 1990 to 1998 remains the pinnacle of the art form. With rebounding de-emphasized in the modern game, it may be a long time before we see a worthy rival.