More Rebounds, More Wins? Not Always
More Rebounds, More Wins? Not Always
For many teams, success on the boards means winning. Then there’s Ohio State and Maryland this season.
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Hall of Fame coach Pat Riley once told reporters that "in Los Angeles, we have a saying, 'No rebounds, no rings.'" There's little argument that rebounding is an important part of winning games and titles. But this season there are teams that have put themselves in contention for conference and maybe national championships by winning games even when they lose the battle on the boards.
Playing without star guard Jacy Sheldon for long stretches of the season, Ohio State has nonetheless compiled a 19-3 record and ranks 13th in the Her Hoop Stats ratings. Despite losses to Iowa, Indiana and Purdue in the past week, the Buckeyes have made a habit of winning even when being out-rebounded, thanks in part to a high-powered offense that generates more points per play than all but seven Division I teams and a pressing defense that forces the country’s fifth-most turnovers per game.
Nine of the team's 19 wins this season have come while posting a negative rebounding margin. That's tied for first with William & Mary and Texas State among all Division I teams so far, and Ohio State is one of just a few ranked teams that have been out-rebounded multiple times in games they've won. Another one is Big Ten rival Maryland, which has no true post player and has won eight times while securing fewer rebounds, including last week's 72-64 win over Michigan.
At this time a year ago, no Big Ten team had won more than five games while being out-rebounded, and for Ohio State it happened only three times through the end of January 2022, meaning they've tripled their number of wins while losing on the boards. William & Mary won just once with a negative rebounding margin through the end of January last year; this year they have done it nine times.
In general, top teams don't win many games while losing the rebounding contest. The teams that have done so this season aren't bad, but they also mostly aren't having the kind of success that Ohio State and Maryland have had. North Carolina has seven wins while being out-rebounded, and teams like Auburn (seven) and Colorado State (six) aren't pushovers.
Neither the Buckeyes nor the Terrapins have enormous size; Ohio State has two players taller than 6-foot-1 on the roster, only one of whom (Rebeka Mikulasikova) plays significant minutes. The Buckeyes also employ a pressing defense designed to produce turnovers and quick shots. Maryland is in a similar situation thanks to injuries to post players. The Terps don’t press as much as Ohio State, but they try to force turnovers through ball pressure and have no true post player among their regular rotation, with Diamond Miller the tallest player at 6-foot-3. There also are teams like Illinois State, which doesn’t press on defense yet has won eight games this season while being out-rebounded.
It's not hard to find support for Riley’s theory in the current season: top-ranked South Carolina has a rebound margin of 20 more boards a game than its opponents, topped only by LSU, which on the strength of Angel Reese's seemingly endless streak of double-doubles currently averages 22 more rebounds a game. Stanford's average margin is five boards lower than the Tigers, but that's still good enough for third in Division I. South Carolina is also the only team among those three who has actually been out-rebounded in a game this season - by Stanford on Nov 20.
South Carolina had the highest average rebounding margin last season - 18 more boards than opponents - on its way to the national championship. Baylor's title team in 2019 led the nation in rebounding margin, too. But those teams had elite post players, so maybe this is a case of selection bias?
To try and figure that out, we can look at what rebounding contributes to a team's wins using statistical methods like simple correlation and regression, where we test the effect of one or more factors on another. Rebounding margin has a solid positive relationship to point differential both this season and last season - the two are about 60-65 percent related, in fact. Like Ohio State and Maryland, that doesn't always mean grabbing more rebounds than your opponent leads to victory, but it's a good start. How much can we explain that relationship? How much difference does rebounding margin make?
As it turns out, rebounding margin can explain about 35 percent of the difference in points between two teams, which is not bad as a predictor but not exactly a slam dunk case, if you'll pardon the phrase. Rebounding margin seems slightly more predictive of point differential than assist-to-turnover ratio is, but the truth here is that there's usually not one thing that will guarantee victory in basketball.
What about defensive rebounding rate? In theory, if a team is better at forcing and securing an opponent’s missed shots it will have more opportunities to score. Ohio State ranks 8th in the Big Ten in defensive rebounding rate, grabbing rebounds on nearly 70% of chances to do so, while Maryland is next-to-last in the conference at 66.1%. And as a single factor, defensive rebounding rate alone isn’t terribly predictive of point differential - it explains about 12 percent of the difference.
Both teams are much better at forcing turnovers - the Buckeyes are tops in the Big Ten, forcing a turnover on nearly one of every four possessions, while the Terps rank fifth. But opponent turnovers aren’t any more predictive of point differential than defensive rebounding rate is, so while it’s one piece of the overall picture, rebounding margin seems to matter more, and the combination of rebounding margin and assist-to-turnover ratio is even more predictive. A strong rebounding margin demonstrates not just how good a team is at forcing opponents to take shots they miss, but also its ability to finish defensive possessions and to crash the offensive glass.
The bottom line: teams can win without dominating the boards, especially if they force opponents into turnovers. But it’s the rare team that can do it a lot, particularly against strong competition. Teams like Ohio State, Maryland and North Carolina have been bucking a trend in the first part of the season; whether they need to continue doing so may say a lot about their chances come March.
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