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I decided to look at the SportVU defensive data for the top eight Rocket's players in minutes played. For your information SportVU data is the seminal analytical tool available to NBA teams. Even the neutered version offered to fans is the most precise measure available of many different metrics in the NBA. SportVU data offers a special look into the defensive prowess of NBA players. Normally we fans are limited to imprecise metrics such as xRAPM. SportVU offers a precise analysis of every play in the NBA, and distinguishes between the specific offensive player versus the specific defensive player. SportVU then rolls all of that data up into an easily digested format.
In this article I will focus on the Rocket's defensive player's ability to reduce the offensive player's FG%. After all that is what NBA defense is all about. There are a number of caveats to this analysis. It does not take into account the Howard effect (The Dwight Effect:A New Ensemble of Interior Defense Analytics for the NBA, MIT Sloan Sports Conference, 2013). I have assumed that the SportVU data properly corrects for the quality of the offensive player. I believe it does, but I have no proof that Westbrook is treated differently than Canaan on offense. That issue is easily solvable. Unfortunately Jones does not have a statistically significant amount of data this season. For that reason I did not include his numbers. Papa is on the borderline, but I did include him. He has four times as many minutes this season than Jones.
The data presented in the following graphs is easily interpreted. The better defender will always hold their opponent to a lower FG%. Therefore the more negative the number the better the defense.
This chart will be the over riding theme of this article. Smith is really really good on defense. And D-Mo is really good. Otherwise it is a mixed bag that I would not have expected. Smith, despite who he guards around the rim is a great defender. Dropping the FG% around the rim from say, 54% to 44%, is actually a huge deal. That reduces an opponent like West to somewhere around the offensive force of a second string power forward like Plumlee. D-Mo, with around fifty percent of his court time at center, effectively reduces a Cousins to a Len. From a powerhouse to an average NBA center. Ariza, Bev and Brewer are obviously over matched around the rim.
This graph documents each players defense from inside the arc to the basket. It is reminiscent of the previous rim protection graph. What this graph really describes is how quick a player is closing out on two point shots, and how effective they are on the close out. And again somehow we again see that Ariza is less effective than other Rockets defenders. A 7.6% over average FG% is huge. More on this later. But I would like to point out that besides D-Mo and Smith, the Rockets cannot effectively defend a player like LMA. It will become obvious later why Howard would not be a great choice to defend LMA.
What really stands out to me in this graph is how darn good Papa and Harden are at defending the arc. Those two players basically convert a Curry into a D-Mo from beyond the arc. And look at D-Mo's numbers. I have little doubt that D-Mo is the fastest seven footer in the NBA. This graph illustrates why the Rockets team is the best in the NBA at defending the three point shot. A minus five percent in opponents three point percentage takes an offense from ~36% to ~31%.
No surprises here. Except Papa being so good 15 feet and out from the basket. The eye test is certainly satisfied that Howard has a difficult time leaving the paint to close out on shots away from the basket. This means that whoever is playing power forward along side of Howard must be great at switching on defense so that they can cover Howard"s defensive outside responsibilities. Howard definitely won't be there 18 feet out.
Less than 10 feet. The paint. Again it becomes obvious that Brewer, Bev and Ariza need help down there. Significant help. However Smith, Howard and D-Mo can obviously handle their defensive assignments down there with little support. I do find Harden's defense to be less robust than I would have expected. But then again it is approximately league average.
And then the overall data. How important is the difference between Smith's -4% and Bev's +2.5%. About 13 points per 100 possessions. At 1.03 points per shot in the NBA. D-Mo's stats do pass the eye test. He is all over the floor, and is great at intimidating shots. Harden's numbers belie the MSM rhetoric that Harden is not a very good defender this season. Brewer, Ariza and Bev are not as good on the defensive side of the ball as my eye test. However their three point defense is obviously the league best. These numbers were much better earlier in the season. Which is why the Rockets are gradually falling in defensive ranking.
A final caveat. Some statistical analysis has shown that Houston's defense benefits from an above league average of missed wide open shots.
....got a few other things that need attention first.
