Arturo Galletti is the Co-editor and Director of Analytics for the Wages of Wins Network. He is an Electrical Engineer with General Electric in the lovely isle of Puerto Rico, where he keeps his production lines running by day and night (and weekends) and works on sport analysis with his free time.
“The only real defense is active defense”
–Mao Tse-tung
One of the commonly heard caveats to the Wins Produced numbers (and in fact for all box-score regressed metrics) is that they don’t fully capture individual defense. The typical argument goes that Player X cannot possibly be that good as he gets killed by his opponent.
Right Boys?
This has always bothered me. Is it really that hard to tell if a player does a better than average job at shutting down their opponent?
I say no.
Let’s take a look at how well each player’s opponent’s did over the course of the 2010-2011 NBA season.Introducing the Wins Prevented rankings for 2010-2011:
The results were downright peculiar.
A few explanations on method before we get to the discussion portion of the program:
- I am looking at the production of the average opponent for each player in terms of Wins Produced per 48 minutes. I do this on a game to game basis by looking at average production by position (as opposed to play by play). What this means in practical terms is that it’s an approximation that’s improves the closer a player’s minutes per game edge towards 48 minutes. To that end I will focus on players with a large sample size (>1500 Minutes played).
- Pay attention now, because this is where it gets funky. When I started looking at this back in the day, I focused on opponent performance versus league average’s. The more I thought about it though, the more unfair that seemed. Players do not get to pick their teammates for the most part. I decided to look at player opponent performance versus the performance of the average team opponent. I want to identify player’s who are better defenders than you would expect based on their team and/or system.
Let’s take a look at the top 20 to illustrate what I mean by peculiar:
Kevin Durant, Dwight Howard, Iguodala, Kobe, Rajon Rondo, Kirilenko and Thabo are not that surprising to me in that Top 20. But Stephen Curry at number 1 was a stunner. Kevin Love, Kevin Martin and Nick Young are also big surprises. To be fair it shouldn’t be, in all those cases the players in question managed to keep their opponents from producing at a significantly lesser rate than the rest of their team.
The Bottom 20 has some surprises as well:
John Wall was a total turnstile for the Wizards and this was not surprising (to be fair he is very,very young) . Chandler being number 2 is a stunner (this may be a function of the Dallas zone defense though). The jaw dropper for me is Tim Duncan, who may very well have reached the end of the road.
Fooled you didn't I?
-Arturo
Wages of Wins Journal 
fricktho
August 11, 2011
You have a metric that shows that the Timberwolves have the best defensive front court in the league. Also that guards prevent more wins than forwards on average. Back to the drawing board.
fricktho
August 11, 2011
WP compares players to their peers at their position. Instead of saying this player is better than his teammates shouldn’t you be trying to isolate him against his peers?
Arturo Galletti
August 11, 2011
fricktho,
Heh. This is just saying that Love and Darko do a better job on their opponents than would be expected based on how ,ummm, opportunity filled their team is on D.
I’ve actually done that before more than once (see http://wagesofwins.net/2011/07/06/the-concensus-mvp-2/). I’m trying to isolate Team performance from player performance here.
Kyle Shook
August 11, 2011
I really think you should remove this before it ends up on the blogosphere and gets ripped apart by dumb people. You have TC as the worst defensive center in the league, even though you try to explain it with the Dallas zone.
I fear people will see this and immediately write off WP and what yall do here at the wages of wins. you’ve done alot of work for WoW and I would like to see more people buy into this stuff, but a post liek this is not not not going to help. It’s too counter intuitive and really just cannot be a good metric to use going forward. I mean, KG is only one spot ahead of Big Baby. There will be riots. (you must have previewed this in London)
I am a full fledged WP/wages of wins believe but this metric needs some work.
Kyle
nolaman
August 11, 2011
Tyson Chandler’s rating in this new metric does not surprise me as an observant long time Hornet’s fan.
Tyson built his reputation for playing good defense as a help defender. He is long and cat quick so he frquently comes swooping in to block shots from the other side of the lane.
But I never thought of him as a good on-the-ball defender.
I quess that raises the question of whether this stat captures good help defense?
Man of Steele
August 11, 2011
Hey Arturo,
Thanks for the article. I’ve read the bullet points about 5 times, but I must be too obtuse (= stupid) to grasp it. Does this metric measure a player’s defensive performance relative to the defensive performance of their teammates? In other words, does the column labeled “Wins Produced by Average Team Opponent” represent the average defensive performance of a player’s teammates?
If so, I think the metric is a good tool for uncovering under-/overrated defensive players. However, as far as ranking the league from top to bottom, I think the relative quality of teammates, which is a corrective at the team level, might distort the comparison. Since not everyone plays with the same teammates, not every player can be as much better than their teammates as a player on a truly horrid defensive team can.
I think this is what you’re getting at in your response to the comment about the T-Wolves’ frontcourt. Or, to pick on the guy at the top, perhaps Steph Curry comes out as the no. 1 defender in the league in part because the Warriors are a team of shooters, and the only player on their team who can defend is the oft-injured Andris Biedrins. In this case, the metric is extremely helpful for the Warriors in that it tells them that Curry was the best defender on their team last year, but that almost every other position needs to improve defensively. From a league-wide perspective, though, I’m not sure that it has the same effect. Should the Celtics consider trading Rondo for Curry, since Curry is obviously the superior defender? More to the point, if that trade did go through, might Curry’s numbers plunge playing on a pretty solid defensive team beside Kevin Garnett and Paul Pierce?
Sorry if this sounds like criticism; it’s actually not intended as such, I’m just trying to get a grasp on the metric. If I’ve misunderstood, please correct me :)
btw, the charts are cool as always!
Arturo Galletti
August 11, 2011
Kyle,
I was looking for a specific effect in this case: How well does the individual player defend/shut down his man vs. how his team does on average. The results are way interesting but have to be taken in context. KG for example plays with horrible,horrible 4/5 and he gets penalized for it. Nolaman’s point is important too, if the player is focused on help defense (like KG or Chandler) particularly because of glaring personnel weaknesses for his team, this will show up here.
My take on D is that Player D breaks down as:
Help D (which shows up on the team side)
Man D (which would show up here mostly)
One problem lies in that if a player is used mostly on help D by his particular team/coach his individual D will suffer (see Chandler, KG and Duncan). Another problem lies in that if the team purposely schemes for Defensive help to always be sent to help a particular player that will show up as well (I believe this is the case with Curry and Kobe).
I’m really not worried about the blogosphere. I think the data is very interesting. Things like the fact that Artest is great on his man and at helping shot down Kobe’s are very apparent.
This is one of those things I’m going to keep picking at over time.
Arturo Galletti
August 11, 2011
MOS,
No worries. You get the gist of what I was going for. Note that I am not really ranking the league top to bottom.
Andy Momplaisir
August 11, 2011
I always thought Stephen Curry was a very underrated defender. I get the feeling that something will be done to go against that, but until then, yes. Stephen Curry is underrated. I keep hearing that he’s not quick enough to guard players at his position that are fast, but they tend to not be able to shoot well and force bad shots (D Rose, Westbrook…). He’s a good defender.
Todd Bogart
August 14, 2011
A lot of great defense takes place before the ball is caught: establishing position and taking away spots. That might rely more on smarts and experience than overt athleticism.