Defense on the perimeter: what do the adjusted plus/minus ratings say?
It has been interesting seeing the reaction to my list of best and worst big men defenders. This writer never claimed for a minute that these were THE definitive lists (in the exact right order) of defensive big men. That is not the nature of statistical evidence. (If we are honest with ourselves, we would realize that this is the nature of most non-statistical evidence as well.)
With statistical evidence we generally are painting with broad strokes because the results are rarely precise enough to distinguish a player rated #3 from one rated #7. That said, these results with a handful of exceptions, do tell us that the players in the "best" lists are better than average defenders and the players in the "worst" lists are not. Context does matter, but watching players who change teams it appears that context does not typically change a defender from an elite defender to an average one.
And remember that these lists are based upon plus/minus statistics that measure how a team defends when a player is in the game versus when he is not. Since how a team defends when a given player is in the game IS what we care most about, when we see odd results we have to ask ourselves why the team defends so well (or so poorly) when that player is in the game.
And remember I am accounting for who a player is playing with and against and for garbage/clutch time play. So for these adjusted plus/minus ratings it does not matter who a player's substitute is, like it does with unadjusted plus/minus ratings.
Now these results are a combination of adjusted plus/minus ratings (based upon three seasons with most of the weight on last season) and statistical plus/minus ratings (based upon just last season) that average in the adjusted plus/minus ratings of players similar to a given player. I get a lot of objections to including this statistical plus/minus rating because supposedly players without gaudy defensive stats will be hurt by this statistical plus/minus ratings.
But players like Bruce Bowen and Tayshaun Prince turn out to be more highly rated by the statistical plus/minus rating than the adjusted plus/minus rating. (On average, players selected to the All-Defensive teams were more highly rated by the statistical plus minus/rating.)
Now again in "Measuring How NBA Players Help their Teams Win" I describe the gory details of how I compute these adjusted plus/minus ratings. (I have made a few changes since then, along with adding another year of data.) So combining ratings of defense from a players' own adjusted plus/minus rating and that of players similar to him, which players are the best defenders? I list the best and worst by position among players playing 1,000 or more minutes in 2004-05. These ratings are predictions for the 2005-06 season assuming that younger players will improve their defense and older players may see a decline in their defense.
And remember if you don't like the ratings (and the player is not a rookie who with only one year of data is more prone to error), ask yourself two questions.
Why does the player's team defend a lot better (or worse) when that player is in the game? Why do the teams of players similar to that player defend a lot better (or worse) when they are in the game?
And now that I have bored you to tears, here are the lists.
Top Six Small Forwards (best to worst):
- Shane Battier
- Darius Miles
- Trevor Ariza
- Shandon Anderson
- Paul Pierce
- Bruce Bowen
Bottom Six Small Forwards (worst to best):
- Peja Stojakovic
- Matt Harpring
- Lee Nailon
- Wally Szczerbiak
- Tim Thomas
- Carmelo Anthony
Remember that Ron Artest did not make this list because he did not play 1,000 minutes last season. The big surprises here probably are Ariza, Harpring, and the absence of Tayshaun Prince.
Ariza is a rookie who did not play a lot of minutes so take his rating with a grain of salt. Harpring has not been an effective defender in each of the last three seasons, but I think last season he was a bit worse because of nagging injuries.
Prince seems to benefit a great deal from playing with the two Wallaces. His raw plus/minus is very good, but once I account for the fact that he plays with the two Wallaces, it falls apart. When he plays without them, Detroit struggles on defense, whereas the Wallaces just do not seem to miss him much when he is out of the game. That said, Prince plays so many of his minutes with the two Wallaces that it is a bit difficult to separate out their relative contributions.
Top Eight Shooting Guards (best to worst):
- Tony Allen
- Andre Iguodala
- Josh Smith
- Ben Gordon
- Aaron McKie
- Gerald Wallace
- Manu Ginobili
- Eddie Jones
Bottom Eight Shooting Guards (worst to best):
- Michael Redd
- DeShawn Stevenson
- Jalen Rose
- Keith Bogans
- Latrell Sprewell
- Raja Bell
- Ricky Davis
- J.R. Smith
For this best list to be dominated by rookies is very different from last season when the rookies as a group were terrible on defense. This season they were quite good and look even better in this list because this is a projection for next year and I would expect their defense to get better with experience. But remember to take these rookie ratings with a grain of salt. We really need another season to get an accurate assessment of their defense using plus/minus ratings.
In particular, Gordon is a puzzle since he has a reputation of being a terrible defender. He played the bulk of his minutes with Tyson Chandler and it appears to me he is getting credit for a lot of Chandler's handiwork because the few times Gordon was in but Chandler was not, the Bulls played great defense. On the other hand, in the few times when Chandler was in but Gordon was not, the Bulls played pretty poor defense.
Statistically, this implies that it was Gordon and not Chandler that was the reason for the Bulls' good defense. And thus he gets more credit for the good defense during the times when they were both in the game. Gordon may be a better defender than he has gotten credit for, but I suspect that part of this is just good fortune. Once we have another season to try to separate Chandler and Gordon, it should be easier to assess Gordon's defensive effectiveness.
And yes, it is Redd who is the max player who is rated the worst defender at his position. The Bucks over the past three seasons have consistently been better when Redd has been out of the game. (In fact, it is striking how consistent the results have been.) And the reason is because he has been a horrible defender - just plain horrible. There has been no player who has played anywhere near the minutes he has over the past three seasons that has rated as consistently horrible on defense as Redd has. But I think what we learn from all of this is that defense may win championships, but it does not pay the bills.
Interestingly, Bell who is being signed by the Suns in order to shore up their defense rates as a bad defender. What is remarkable about Bell's results is that he has played for several teams over the past three seasons and yet his defensive ratings have been consistently bad. That strongly suggests that putting him in a new context with the Suns is not going to markedly improve his defense.
Top Five Point Guards (best to worst):
- Chris Duhon
- Marcus Banks
- Earl Watson
- Jason Kidd
- Eric Snow
Bottom Seven Point Guards (worst to best):
- Troy Hudson
- Tyronn Lue
- Tierre Brown
- Damon Stoudamire
- Carlos Arroyo
- Nick Van Exel
- Leandro Barbosa
Interestingly, two of the best defending point guards (Duhon and Watson) are still available in the free agent market. Now again we only have one season with Duhon (but a lot of minutes in that season and results that are consistent across the adjusted and statistical plus/minus ratings), so we should be a big skeptical of his results. But Watson has consistently over the last three seasons been an elite defender at the point guard position. He seems to be another example of the adage that defense may win championships, but it does not pay the bills.
Lue has a reputation of being a good defender, but like Bell he has played in a number of places and consistently been an ineffective defender. His reputation must rest pretty heavily on his play in the Finals when he was somewhat effective against Allen Iverson. That performance has stuck in people's minds in face of conflicting evidence.
For more comments about this methodology and these results from some of the top basketball statistics experts, as well as lots of other interesting discussions about basketball statistics, see the APBRmetrics message board.
Last updated: 5:00 AM, August 2, 2005