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“The Dwight Effect” and Kevin Garnett

We all know Kevin Garnett is an elite defensive player.  Upon his arrival in 2007, the Celtics jumped from the 16th best team in defensive efficiency for the 2006-2007 season to 1st at the close of the 2007-2008 season.  While that shift to the upper echelon was due in large part to the arrival of defensive guru Tom Thibodeau that same year, Garnett’s instantaneous effect on the defensive culture in Boston can not be overstated.

Flash forward six years.  The Celtics have had five successive seasons of finishing with a defense that is top five in efficiency (6th so far this season).  Three years prior, Thibodeau had bolted Boston for a much deserved head coaching gig in Chicago.  In the three years sans Thibs,  Doc Rivers has continued to preach the defense-first mentality, something engrained in the roster holdovers from that championship season. After Thibs’ departure, the Celtics even hired another defensive maestro in Lawrence Frank to prevent any defensive drop-offs.  It all worked.  However, the Celtics’ sustained defensive prowess has only had one real constant aside from Doc Rivers: Kevin Garnett.

Garnett’s on-court quarterbacking has become stuff of legend.  His defensive rotations are sharper than Santoku Knives. His pick-and-roll defense is lethal.  All anecdotes of Garnett’s defensive abilities will be recorded in the annals of NBA history, to be retrieved 50 years from now when codgers like me want to educate the young, uninitiated in dank Boston bars about what it truly means to dominate defensively.  It’s a good thing advanced statistics exist. When I’m regaling those young basketball fans of the legend of  Garnett as a Boston Celtic – telling them about how LeBron James never scored on him– I’ll be able to utilize this quantitative analysis to substantiate anything I haven’t exaggerated or embellished.

Defense is a difficult aspect of the game to properly evaluate.  We have things like defensive ratings, on-court/off-court numbers, defensive rebound rates, and block rates to name of few go-to statistics that help shape a particular player’s defensive narrative.  In the future, we will be able to deconstruct these numbers even further.  If you were to believe Kirk Goldsberry and Eric Weiss, the future is now.

I love things like defensive rating and on-court/off-court numbers, but they lack the depth necessary to really properly evaluate a player’s defensive ability.  Goldsberry and Weiss have shoved a Z-axis up this two-dimensional plane through their usage of spatial analysis.  At this years’ MIT Sloan Sports Analytics Conference, they presented a paper entitled “The Dwight Effect: A New Ensemble of Interior Defense Analytics for the NBA.”  The paper’s goal was to, well, I’ll just let them tell you:

The core objectives of this paper are 1) to improve the characterization and understanding of interior defense in the NBA, and 2) expose key challenges associated with measuring defense as new forms of performance data emerge. We present case studies that 1) use spatial analyses to extract new defensive metrics from optically tracked game data (SportVu data) and 2) use visual analytics to present results.

Makes sense? No? From what I understand about really smart endeavors – which, is admittedly very little – Goldsberry and Weiss want to expand the limits of defensive metrics and provide context to these numbers through the usage of spatial analysis.  These two nerds want to add two components to measuring defense: 1) how close the defender is to his offensive counterpart; and 2) where they are on the court in relationship to the basket.  I call them “nerds” both affectionately and with a hint of jealously.  This stuff is just so FREAKING cool.

The findings of the paper were even more interesting.  Even though the paper was titled “The Dwight Effect,” Larry Sanders proved to be the best interior defender in the NBA.  This is not so hard to digest given Sanders’ length, athleticism, and energy.  The real Scooby Doo moment came when Goldsberry and Weiss revealed that Andrea Bargnani was one of the top five rim protectors.  Since they knew that to be false, Goldsberry and Weiss surmised that Bargnani was a beneficiary of their proximity variable.  The data was based on defenders being within five feet of their opponent and there’s a good chance that Bargnani was often too far away from his man and thus reduced his sample size (I could also see the Steve Novak effect being a possible explanation).  Whatever the reason, Bargnani sucks.

Speaking of sucking, David Lee registered so low in this study Goldsberry and Weiss made a video tribute of his bad defense.  This was the real benefit of being in the audience at Sloan. The highlight of Day 1 was watching the inexplicable defensive “strategies” employed by Lee, against a counterpoint of Goldsberry’s pleasant, matter-of-fact monotone narration. Unfortunately, I couldn’t find that video and it would be without narration if I could so you’ll have to settle for the closest thing I could find to David Lee playing defense.

Absent in all of the analysis is Kevin Garnett.  While not specifically known for being a rim protector (he’s more of a master-of-all-trades defender) I was still surprised when Garnett didn’t make the top-five. He actually didn’t even make the top-ten.  Based on Goldsberry and Weiss’ research, here is where Garnett ranked:

If I’m interpreting this data set correctly, 54.4% of the shots Garnett defends are in close proximity to the rim and his opponents are shooting 48.3% on shots within five feet of the basket.  Not bad ranks at all, but still not the elite level you associate with Garnett.  It’s worth mentioning that these numbers are based on Garnett being within five feet of his defender.  Based on the Celtics’ semi-complicated rotational schemes, Garnett could be a victim of his less-talented teammates blowing an assignment and Garnett having to retreat to within five feet of an opponent’s easy hoop.  This is speculative, but when Garnett is counting on guys like Brandon Bass and Chris Wilcox to make their rotations, it’s definitely in the realm of possibility.

This could also mean that Garnett is not as effective a rim protector as he once was.  The data for this study is from only the last two seasons and that’s hardly enough to make any definitive statements about someone’s career.  It’s reasonable to think that Garnett has declined over the past two years, given his advancing basketball age, the tread on his tires, and his decrease and athleticism.

Here’s what we do know: Garnett is still an elite defensive player within the Celtics’ system.

Here’s how we know it: When Garnett is on the bench, the Celtics give up 109 points per 100 possessions.  When he’s playing, that number comes down to 100 points per 100 possessions.  According to mySynergySports, Garnett’s opponents’ overall FG% is 35.5%.  According to my memory bank, Garnett has yelled, “by yourself,” “get him,” and “get that [stuff] out of here” 9,457 times.

Add (figuratively!) the two together (Goldsberry/Weiss and traditional defensive metrics), and you would have a great candidate for the NBA’s Defense Secretary.

It’s possible that people smarter than I can poke holes in Goldsberry and Weiss’ analysis (like this guy) but it certainly adds a new dimension to the evaluation of individual defenders.  There are plenty of things I left out so if you have the time, check out the paper and/or watch this video.  Both are well worth your time.

  • fabzzz

    Great article.

    As an aside, just read the five on five for the east playoffs and the power rankings.

    Some interesting conclusions…all five believe the Celtics have best chance at an upset and the power rankings currently has them as the fourth best team in the east. If we beat Indiana tonight and the hawks on Friday then all of a sudden the Celtics could be considered the third best team in the east.

    This is a huge week for the Celtics. Still I’m convinced the sixth seed is best for us.

  • Yogesh

    Check how many shots other teams get at the rim when KG is on the floor and see how he ranks there.

  • hydrofluoric

    KG is not a rim protector in the sense that Dwight Howard or the '90s centers were, where if he was camping in the restricted area, you were scared to drive at him. (See: Spencer Hawes torching KG last night off the dribble from 7ish feet, LeBron "with no regard for human life")

    KG's unselfishness gives him less dominant individual stats. He's not high in blocks or in steals; he doesn't stop people particularly well at the rim anymore; he can be bullied by the right post players. But his true defensive value comes at the perimeter helping to contain penetration. Measuring Kevin Garnett by what he does close to the basket is definitely a bad idea.

    • Rav

      Not high in steals? He has more steals for his career than any big man except Olajuwon and Karl Malone. He's also top 20 in blocks, which underrates him somewhat due to the time he's spent defending on the perimeter (unlike most of those ahead of him who were rooted to the paint). He also leads in blocks after the whistle :)

      It's hard to quantify how much of a "deterrent" factor one player has, and how much that underestimates his rim protection ability (e.g. Dwight would have more blocks if people weren't so scared that they simply avoided him). We could see how many at rim-attempts are taken by the opposing team, and compare to league average (like Yogesh mentions above), but there are still too many other variables (e.g. how good are the other defenders at stopping dribble penetration).

      KG was definitely formidable at the rim during the prime of his career, especially with his athleticism, length, timing and determination. He's one of those few who have grabbed an opponent's shot in mid-air. In his old age, he's obviously less of a challenge, hence people like Hawes trying their luck. But using Lebron as an example is a poor argument – Dwight Howard et al. have been dunked on numerous times as well, by much lesser players.

      • hydrofluoric

        Right you are on the blocks and steals stats, thanks for the correction. I shouldn't try to extend the findings and the KG of recent seasons to those of the past.

        I think that it's at least fair to say however that the data in Goldberry's article confirms the eye test – that at least currently, isolating instances where KG is under the rim does not bring out the best of him.

  • elroz

    With Dwight, the Lakers defense is still shit. Bargniani is a waste.

    KG has been a defensive staple for years. Enough said.

  • mmmmm

    I agree with hydroflouric's comment.

    While is is certainly true that KG is a very good defender close to the rim – that is not at all where his true value as a defender surfaces.

    KG is at his best when he is partnered with a low-post, weak-side big who's primary job is to 'protect the rim' and provide weak-side help and not a lot else. Give KG that, and then he becomes the ultimate high-paint defender.

    In 2008, when KG had a healthy Kendrick Perkins as his true 5 behind him, the C's interior 'At Rim' opposing FG% was just a tiny slender hair below average at 60.1%. So Perkins was a good stopper but not an absolute wall. The more interesting statistics about that from that season were that the number of attempts at the rim was dead last (only 20.1 per game) AND that the percentage of At Rim shots that were _assisted_ was the second lowest (only 49.3%). So basically, only 10 at-rim attempts per game were the result of assists. To me, this is testament to KG's legendary control of the passing lanes.

    Only one other team had a lower assist rate on At Rim shots that season, Phoenix (46%), but they gave up a lot more shots at the rim (35% more per game than the C'). If I recall, that was basically because they gave up a ton of transition fast break opportunities. So they were really just giving up several additional unassisted layups per game and that is why their assist rate was low. Their assist rate was probably much higher on at rim shots taken from the half-court.

    With his phenomenal horizontal game, his reach and his ability to quickly hedge and recover, KG's true talent has always been simply in denying team's the ability to get the ball into the interior. All you need is add a good 'vertical' defender to hold the post behind him and you have an instant top-of-the-league interior defense.

    This is why so many otherwise unremarkable 'big men' defenders have been made to look SO good in terms of DRtg when on the floor with KG. He makes their job easier. Guys like Shaq, Semih Erden, Ryan Hollins, Nenad Krstic, Chris Wilcox, Glen Davis, Brandon Bass – none known as great defenders otherwise – all posted great DRtgs when on the floor with KG.

    Big men who have actual above-average defensive skill, such as Perkins, Jermaine O'Neal, Greg Stiemsma – they posted sometimes ridiculous low DRtgs working behind KG.

    The last couple of years have been tough. Since Shaq's injury and then Jermaine, Perk … the long list … it has been difficult for the C's to keep any competent 'true big' healthy and on the floor next to KG for extended run. Brandon Bass has stayed healthy, but being undersized, he often forces KG to have to move to the 5 and be the 'rim protector' too much. The C's have learned how to make that work, but it has never been as effective defensively as when they have a guy with real length who can play the 5 post and let KG roam as the high-paint defender.

    • 12345

      Sry man… I accidently hit the dislike button, when instead I was trying to like your comment. :/

    • skeeds

      Excellent! That was exactly my thought after reading this article. The way the Boston defense works, KG shows hard on the pick an roll and basically looks to close out the passing lanes, pretty much obliterating the handler's ability to swing the ball to the weakside or find a cutter.
      It took me a while to figure out. I knew KG was a fantastic defender, yet he plays his own man too loose. It looked paradoxical. That's why help defense is the Celtics Bible though. On a good day, as soon as KG looses his man he calls it, the other big instantly looks for him and the weakside wing collapses. When the C's rotations get crisp (by April every year), opponents' pick and rolls stop working.
      This is why I keep complaining that Ainge HAS to get an athletic big. Suuuure, any team wants a DeAndre Jordan, but for us, as you very well say, a vertical defender is crucial. All this team needs to have the perfect defense is someone to contest at the rim. That's why the C's were so impossibly good defensively with Perk, (and even JO).
      Not to mention that it's nothing short of frustrating to have all this space KG creates on offense with his range, and have no one there to catch an easy lob…

      • tbunny

        Uh apparently not every team wants DeAndre Jordan.

  • boston craze