Henry Abbot, senior writer at ESPN and founder of the TrueHoop blog and network (of which Roundball Mining Company is proud to be a part) recently published an interesting article entitled “Offensive rebounds come with a cost.” In it, in response to John Hollinger’s observation that last season’s Boston Celtics were the worst offensive rebounding team in league history. he poses an intriguing question:
Let’s say Doc Rivers told his bigs to crash the offensive boards more. They would certainly get more easy putbacks in particular and more field goal attempts for their team generally. More shots per possession. Better offensive efficiency overall.
But at what cost? How much would the team be giving up on all those possessions where the bigs didn’t get the rebound. That’s the most common outcome, right? In those cases, the bigs would simply not be back which hurts the team, for sure. Does it hurt the team more than now-and-again offensive rebounds are worth?
He went on to point out that the three teams last season which had the fewest shots per possession were Boston, Miami and Oklahoma City, summarizing that “a good chunk of the very best teams in the league, including both Finals competitors, simply don’t seem to place much of a priority on the offensive glass.”
On its face, there is a logic to this that seems completely reasonable. If you’re not back on defense, how can you defend? In fact, I did not question it at all at first. My thoughts immediately went to the implications of this concept for the Denver Nuggets. They place a premium on scoring at the rim, which most definitely includes second chance points scored off offensive rebounds.They also are seeking to improve their defense, which slipped last season.
Mulling his over, I first wondered aloud on twitter whether the (apparent) defensive harm resulting from prioritizing offensive boards might be minimized in Denver’s case due to the speed and athleticism of its frontcourt – or in other words, whether it would be offset by their ability to get back more quickly than many other teams’ bigs, even after going for offensive boards
I quickly got a reply from twitter user Ty Hicks (@Ty_Hicks), who wasn’t buying any of it. He pointed out that the Thunder and Heat were “hardly the worst in the league” on the offensive glass – 10th and 18th in offensive rebound rate, respectively – and that an alternative explanation for their low shots per possession was the fact that “they miss less than other teams.
These arguments raised some valid questions. Would a closer look reveal that there really is any meaningful correlation between a sustained effort to crash the offensive boards and poor defense?
Although the concept does make sense on paper and is appealing in its symmetry, after digging a little deeper into the data I found that I must humbly and respectfully disagree with Henry Abbot and accept that the answer to this question is most likely, “No.”
Using statistics from Hoopdata.com, I put together the chart below. It graphs the relationship between defensive efficiency and offensive rebound rate for every team in the NBA from 2006-07 to 2011-12.
As you can see, the results are quite evenly distributed across the board. There do not seem to be any significantly concentrated clusters of results in the areas where we might expect to see them (very good and very bad offensive rebounding teams with inversely bad/good defensive efficiency) if this hypothesis were true. Additionally, while the linear trend line does show a nominally upward (ie. worse) inclination in defensive efficiency as offensive rebound rate improves, it is very slight. I’m not a statistician, but I would presume that this effect is so minimal as to be insignificant, and within error bars.
I certainly do not claim that this quick analysis is thorough or sufficient enough to completely falsify the hypothesis that a team’s defense will take a hit if they focus too much on the offensive glass. Perhaps a more detailed look involving transition defense specifically, or a larger data set from a longer span of seasons would turn up different, more positive results.
But provisionally, based on this first survey of the correlation between the two factors, it does not appear that going after those offensive boards has a measurably negative impact on defense. Surely not enough of one, at least, to forgo the benefits that offensive rebounding reaps.
So Faried, McGee, and the rest of you Nuggets hungry for those offensive boards, have no fear. Crash that glass. But after that, please, don’t forget to run back.Follow me on Twitter