This work would not have been possible without the help of Ian Levy at Hickory-High. Ian supplied the XPPS data required to crunch all of this
Spoiler alert. David Lee‘s bad defense may be overrated. Yes, it looks ugly. From YouTube, to the sidelines, to infographics, it may be the ugliest D we’ve seen recently. Yet, when we examine the Warriors defense over the last two seasons, we’ll find that their woes lie elsewhere.
David Lee flunks the eye test
At Sloan this year Kirk Goldsberry revealed something that everyone knows. David Lee is terrible at defense. Kirk perfectly demonstrated this with two amazing executions of the eye test. The first was a video compilation of David Lee doing nothing on defense. The next was his now famous image:
What better way to show David Lee’s terrible defense? On the left we have the pinnacle of defense: Larry Sanders. His heat chart is nice and green. In the middle we have the average center. They have a little red but are mostly yellow. And David Lee is lit up like a christmas tree.
Last season the Warriors had the fourth worst defense in the league behind only Charlotte, Sacramento and New Jersey. This season they’ve improved to be just about average. Our question needs to be, how much of David Lee’s terrible defense is behind this? The answer is quite surprising.
Where you shoot from matters
Ian Levy at Hickory-High has developed two amazing metrics - Expected Points per Shot (XPPS) and Points per Shot (PPS). Namely, how well should a team score based on their location and how well do they actually score? Here’s brief breakdown of the locations Ian tracks
The interior is one of the most important places in the NBA. It turns out shooting above 50% is hard. The interior is the one place teams can actually do this. As David Lee is terrible from here, we’d expect the Warriors problems on defense to come from the interior. Do they? Nope! Let’s review!
The 2012 Warriors: Bad at D but not on the interior
The Wins Produced formula has actually had the calculation for defense in it for years. Ian’s great work has allowed us to break down how much defense at each range is worth to a team. The simple explanation is if we examine the rate our opponents are scoring in each region, we can see how many wins we earn or lose. In 2012 the Warriors allowed their opponents to score many points. What was the cause?
First, they let in many many three point shots from above the break. They were bad at defending these. Their opponents shot 36.5% from that range last season, which put the Warriors second to only the Nuggets at poor three point defense! Next, they let their opponents take a lot of these shots — they placed fourth in the league behind Dallas, Denver and Miami.
Their next major flaws was free throws. Now, David Lee did lead the Warriors in personal fouls last season. However, when we control for per-minute foul rates for players that got over 500 minutes last season, David Lee ranked 8th on the Warriors! When we control by position, the major culprits foul wise were Andris Biedrins, Nate Robinson and Klay Thompson. We can perhaps blame some of Biedrins fouls on Lee. If Lee has poor D and Biedrins has to help, he may foul more. That said, Robinson and Thompson point to another possibility — the Warriors perimeter D was terrible last season.
2013 Warriors – Better?
This season a bizarre turnaround has happened. The Warriors actually have really good Interior defense. In fact, they’ve earned 3.1 wins from this. I feel I should explain. All teams allow some number of interior shots each game. The Warriors are actually worse than most teams when it comes to opponent efficiency (blame David Lee if you want!) However, the Warriors allow the 6th fewest interior shots in the league! In fact, Kirk made this point – the shots teams don’t take matter too! We see the Warriors opponents seem to taking more interior shots outside of the restricted area and earning some ground. That said, overall the Warriors interior defense is actually very good this season!
Once again we see the problem lies in three point shooting. I feel we should point out two critical facts here. Last season the Warriors were terrible on perimeter defense. This year, they’ve actually improved. Their opponents shoot 33.3% from above the break. This is considerably below average (35.1%) It seems that teams still think the Warriors are bad at perimeter defense though. The Warriors’ opponents have attempted by far the most above the break three pointers at 1237. The Houston Rockets are in second place, over 125 shot attempts behind!
Teams should take note that this strategy works! At four wins, the massive amount of three pointers explains almost all of the Warriors subpar shooting defense this year. A key reason behind this is that it is very hard to shoot 50% or above. In fact, no team event comes close from outside of the restricted area. Thanks to the extra point the three point line provides, shooting 33.3% is much better than almost any other shot available.
A last point, the Warriors’ defense is actually average this season, despite the chart showing negative wins. The reason is that their defensive rebounding rate is very good. Guess what David Lee has been doing very well this season?
In the end, we see that while it is easy to point at David Lee’s poor defense, it is not the driving force behind the Warrior’s defensive woes. It’s possible if David Lee did learn proper footwork and hand movement that the Warriors could excel and be like the Pacers or Grizzlies on defense. And yes, this would improve the Warriors a lot. However, it seems silly to point at David Lee as a primary culprit when we can clearly see that the Warriors have many other issues that need addressing first.
In sports we often want to focus on solving the problems we can see. Things like David Lee’s terrible defense stand out. It’s worth asking how much it matters though. As with all stats, if we don’t figure out the value of the problem, we risk over compensating on the solution. And while I enjoy a good poke at David Lee’s expense as much as the next guy, it seems to be the wrong place to look for the Warriors.