How important is rebounding when evaluating basketball players?

Coaches and players will often discuss the importance of rebounding. I think defensive rebounding is something that isn't that important at the individual level, but is important at the team level.

Introduction

The box score can certainly be really helpful when starting to analyze how good someone is at basketball, and when I say the box score, I just mean the basic stuff like points, rebounds, assists, steals, and blocks. I guess you could say that players who score more, assist more, steal more, and block more are generally better players. Of course, there are millions of nuances with each of these statistical categories, which is why we watch films and analyze advanced stats. In my mind, rebounding is not inherently one of those stats. Among the high-level statistical categories, it seems a bit outdated and unimportant to me. Almost as if when scorekeepers first started tracking stats, it was something that was relatively easy to track, and we never moved away from it. If you looked at the list of the top 25 scorers in the NBA by points per game or the top 25 passers in the NBA by assists per game, I think you would see many more of the actual best 25 players than if you looked at the top 25 rebounders.¹

I was thinking of the different categories I use to analyze how good a basketball player is, and I realized that defensive rebounding in particular (I’ll talk about offensive rebounding more later) was very low on my priority list. I think the conclusion I came to is that defensive rebounding is something that’s relatively important for teams, but not as much for individual players. What I mean by this is that if player A versus player B takes a shot for a given team, those two possessions can end up in very different places. If player A versus player B is driving to the paint and trying to create a shot for a teammate, those two possessions can end up in very different places. If player A versus player B is guarding a pick and roll, those two possessions can end up in very different places. But if player A versus player B grabs the defensive rebound, I think those possessions end up in basically the same place. Does it really matter if Russell Westbrook grabs the rebound himself or if Steven Adams grabs the rebound and then passes it to him? I don’t think so.

I’ll talk through some data on how important rebounding is to team success, talk a bit more about what it means for individual players, and also discuss offensive rebounding.

Team rebounding and net rating

First, I want to look at the relationship between team rebounding and net rating.² To do this, I gathered rebounding data from the NBA website from all thirty teams over the last 10 seasons.³ Total rebounds per 100 possessions is a highly significant and meaningful predictor of net rating, as an additional rebound per 100 possessions is associated with a 1.21 change in net rating.⁴ See below for the regression scatter plot showing this positive and statistically significant predictor.⁵ Teams that are better at rebounding are generally better teams.

Next, I want to draw a clear delineation between offensive rebounds and defensive rebounds. Defensive rebounds are a highly meaningful and statistically significant predictor of net rating, as an additional defensive rebound per 100 possessions leads to a 2.07 point increase in net rating (really large!).

Offensive rebounds are a different story, as offensive rebounding is actually negatively correlated with net rating. Teams that grab an additional offensive rebound per 100 possessions have a net rating decrease of -.19 over the last ten seasons.

It’s highly important to separate rebounding at the team level and the individual level. It makes sense that good offensive rebounding teams are worse on average: they probably have worse shooting and spacing, and have to compensate for that with offensive boards, and they also probably crash at the sake of transition defense, which is the most efficient form of offense for their opponents. Similarly, good defensive rebounding teams are probably just good defensive teams in general, as they generate stops and secure the boards. I will later make an argument about why I think offensive rebounding is a more important skill for individual players, but these data show that defensive rebounding is more important at the team level.

I think this speaks to a more interesting point about basketball as 1+1≠2. Individual actions in basketball don’t just aggregate nicely. It would follow that if individual offensive rebounding is more important for each individual player, then it would be more important for the team, but it doesn’t work that way; the game is highly nuanced.

The point of basketball is not to get the rebound

When I think about the traits that make someone a good basketball player, I like to think of “value driving actions.” That is, what things does a player do on the court that other players simply can’t replicate that helps their team improve their point differential. Things like scoring, creating a shot for a teammate, or forcing the defense into a miss. But grabbing the rebound itself isn’t really the driving value of the possession, as it is simply a more easily replaceable skillset. A good example of this is the following hypothetical, which I got from the Thinking Basketball podcast. Kobe Bryant drives to the paint and gets double-teamed. He finds Kwame Brown for the open dunk, and the Lakers score two points. While Kwame is the one who puts the points on the scoreboard, Kobe’s playmaking is the thing that drives value in the possession. You could probably put any NBA-level big in Kwame’s position, and the possession ends the same. Yes, some bigs are taller, more explosive, have better positioning and catching skills, but in general, most can finish the play properly. But the ability to draw two bodies in the paint and deliver the interior pass in traffic is something only the great players can do. I think the same way about getting defensive rebounds. Many people can do it, and if one player grabs 6 boards a game and another grabs 8 boards a game, 1) I don't think that tells you much about the difference in inherent rebounding ability, and 2) I also don't think one player is significantly impacting the game more.

To expound on the first point more, consider the importance of matchups and role responsibility. Consider players like Bam Adebayo, Myles Turner, or Jaren Jackson Jr., three highly switchable bigs that spend a lot of time on the perimeter. This means that they inherently have fewer opportunities to grab rebounds because their value is really high switching out onto guards and blowing up actions. They might not average as many rebounds as people “want them to” but they still impact their teams in an overwhelmingly positive way. This has nothing to do with their inherent rebounding ability, but everything to do with their ability to excel in other areas of the game. Team philosophy also plays a role. The Houston Rockets have made it their identity this season to crash the boards regularly in large part because they have no shooters and so have to find ways to score opportunistically in transition or on the glass. Most players would find their rebounding numbers increase when traded to the Rockets, but that’s just the Rockets saying we’re willing to sacrifice transition defense for offensive rebounds and doesn’t say anything about the inherent value of the player or the inherent skill of the player from a rebounding perspective.

In general, the goal is not to grab as many rebounds as possible. The goal of basketball is to limit the opponent's points per possession while maximizing your own points per possession. Yes, rebounds are the most common way for possessions to end, but there are many other ways a possession can end that result in a defensive stop without grabbing the rebound.

Offensive rebounding and Jayson Tatum

Offensive rebounding is a bit different because I evaluate that as a relatively significant component of a player’s off-ball value. It’s well documented that possessions that come after an offensive rebound are highly efficient for teams, as they usually lead to open threes or layups. In the playoffs, the possession battle is really important, and usually the team that simply gets more “shots on goal” ends up on top. For non-shooters, offensive rebounds are almost essential as a way to stay on the floor and drive value.⁶ There are, of course, reasons why offensive rebounding numbers may not be indicative of true offensive rebounding ability due to similar reasons like role and scheme differences.

I am not claiming that rebounding is not important, and so I just want to emphasize that with an example. Wings that are able to rebound at a high level can be really important because they allow you to have a certain level of lineup flexibility. Jayson Tatum is probably the best example of this. Throughout the season and the playoffs this year and last year, the Celtics would often run Tatum as effectively the center on defense. They are able to do this in part because they aren’t really giving anything up on the glass. Tatum is an excellent defensive rebounder for his position, and this allows the Celtics to put out some more flexible and switchable lineups.

In conclusion, I think rebounding is an important skill, but it is highly overrated in discussions among casual NBA fans. When comparing two players, their ability to rebound would rarely be something I would use as a differentiating feature, as I just don’t think it’s enough of a value-driving action.

A little bit about me

My name is Spencer Tyson, and I’m a current senior at Harvard studying applied mathematics. I’m originally from Maryland and really enjoy watching the NBA. This is my fifth article and I plan to write about lots of different topics. I’ve posted on Twitter/X for a while (@SpencerTyson8) and thought this would be a fun senior spring activity. Leave a comment if there are any interesting topics you would like to see. This post was inspired by a friend who knew I thought rebounds were overrated, but then saw the clear value of offensive boards, especially in the playoffs. I have no idea where this blog will go, but I’m just doing it for myself and my own entertainment. Subscribe below!

1. Again, points per game and assists per game are highly flawed stats as well, but they still tell you a lot more about player impact than rebounding.

2. For my readers who don’t know, net rating is how many points a team outscores its opponents per 100 possessions.

3. I’ve been doing a lot of hand-collecting of data over the last few months…

4. A 1.21 change in net rating is very large.

5. Standard OLS regression with fixed effects for year-over-year changes in league-wide net ratings.

6. Think of like a Josh Hart or one of my favorite players, Amen Thompson.