NBA

Nylon Calculus: Westbrook’s triple-doubles, stat padding and team strategy

What exactly is it about Russell Westbrook’s triple-double season that we find extraordinary? I ask this question not to downplay the accomplishment’s historical significance or intrinsic value, the first of which I grant and the second of which I set aside for the moment. I ask this question as a matter of precision. After all, we’re talking about a player who had 23.5 points, 7.8 rebounds and 10.4 assists per game last year — the first double-double average of his career. In light of this baseline, what has he done markedly better that the triple-double statistic itself somehow captures?

Westbrook, of course, has become the undisputed fulcrum of the Oklahoma City Thunder’s attack. He has impacted games in diverse ways. But, even without the triple-doubles, we can see this shift through his higher shot volume, usage rate, assist percentage and other metrics that aim to measure specific player skills. His overall contributions are reflected in both Box Plus/Minus and Real Plus-Minus. What does his pursuit of Oscar Robertson’s milestone tell us about his performance above and beyond what these numbers already do? Or, perhaps more constructively, if we accept Westbrook’s triple-doubles as the starting point for further player analysis, how can we make it a productive exercise?

In many ways, the triple-double discussion boils down to rebounds. Westbrook’s track record suggested that double-digit points and assists were well within his capabilities, and Kevin Durant’s departure only stood to bolster his chances of meeting (and, indeed, far exceeding) these thresholds. It was less clear how his rebounding numbers might change. For example, in the 2014-15 and 2015-16 seasons, Westbrook’s total rebound percentage was 11 when Durant was on the court and 12 when Durant was off the court. The data were similar with Serge Ibaka in the mix. Assuming the percentage-point or so difference was meaningful in the first place, it was hard to tell whether it would be enough to push Westbrook across the 10-rebound mark. But now that he’s there, we can examine how he’s managed to boost his stats on the glass.

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SportVU is built for such close examination, and it reveals a particular type of rebound that Westbrook has augmented this year:

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Compared to the previous three seasons, Westbrook is grabbing three uncontested defensive rebounds more per game, accounting for the vast majority of his rebounding growth. His 7.7 average momentarily leads the league. Among players with at least five defensive rebounds per game, he has the highest proportion of the uncontested variety.

To a degree, it’s unsurprising that a guard’s rebounding improvement would come this way. Unless he makes an unlikely commitment to box out down low with greater frequency (an approach that invites all sorts of potential issues), contested opportunities would seem limited, at least on the defensive end. Nevertheless, a skeptical look at Westbrook’s numbers would be justified.

Uncontested defensive rebounds tend to be the province of players who allegedly “steal” from teammates and pad their own stats. A more objective interpretation, put forth by Seth Partnow last year, estimates that such rebounds are worth about half as much as others, since the defense is bound to secure the ball rather handily under the circumstances, regardless of the individual defender who is ultimately credited. Basically, uncontested defensive rebounds are relatively weak reflections of a player’s ability to gain possession. If Westbrook’s reaching triple-double levels by increasing them, it may not necessarily indicate sharper rebounding skills. Team and game contexts could simply be working in his favor.

But just because the stars are aligning toward gaudy individual numbers doesn’t mean the collective good is compromised. Sometimes, it has value to the team. In a recent TrueHoop podcast, Royce Young hypothesized that Westbrook’s rebounds are welcomed because of their potential benefits:

If you watch Thunder games — and I can’t confirm this — but it certainly appears that Russell Westbrook’s teammates are kind of in on this, because there are times where they see Russ going for a rebound and they say, “Russ, you go get that rebound.”

[…]

They want Westbrook rebounding the ball because they see that as one of their best chances to turn defense into offense. You get the ball into Westbrook’s hands as quickly as possible and… he can turn just an ordinary defensive rebound into a fastbreak opportunity.

Fastbreak opportunities are desirable for teams like the Thunder, whose halfcourt offense is mediocre at best and must be supplemented by more dynamic options. Oklahoma City dedicates 17 percent of its possessions to offensive transitions, the highest rate in the NBA. Its effective field goal percentage of 63 ranks in the top 10. While turnovers can be reduced, the fact remains that pushing the ball up the court is a good strategy overall, especially when you consider the alternatives.

There’s some evidence that offensive benefits are enhanced when Westbrook himself collects the defensive rebound:

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This table captures all of the Thunder’s field goal attempts after defensive rebounds while Westbrook is on the floor. When he takes the rebound, they have a higher effective field goal percentage than when a teammate does. They also attack a tad more quickly. Granted, the sample size is small, and there are many other variables (free throws, turnovers, etc.) that a deeper analysis would consider before sweeping conclusions are drawn. But, intuitively, these preliminary numbers make sense.

A Westbrook defensive rebound eliminates at least one pass and, in cases where possession is guaranteed, perhaps gives the Thunder big men a running start. It puts Oklahoma City in position to generate additional offensive transitions. It has enough potential upside to make the idea worth trying, so you can understand why Billy Donovan might, in Young’s words, “push for” it. Here’s a case where Westbrook’s distinctively aggressive play can be leveraged to advance team concepts.

In sum, although triple-doubles represent individual triumphs, they’re shaped by dynamics within a group setting. These dynamics often manifest themselves in how statistical credit is allocated when multiple people contribute to an outcome. But they can also stem from a deliberate strategy to exploit a competitive edge. If you have a player of Westbrook’s caliber, you unleash his talents in support of team principles.

Editor’s Note: This phenomenon was also covered in detail on NBA Reddit.