Defensive ratings part 2

[ziggy]

Defense on the perimeter: what do the adjusted plus/minus ratings say?

By Dan T. Rosenbaum

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.

 

[Derek Bodner]

That's my boy Iggy!

[rickortreat]

Oh, so his methodology is weighted for things like clutch and garbage time.  Good too see Iggy getting some credit for the work he did, along with Aaron Mckie (though I didn't see very much of him last year!)

One thing I wonder about is where is AI on the list?  Last year at the point, he was scoring a lot and making a lot of assists, not to mention being at the top of the steals list.  Other teams may have scored on the Sixers when he was in there, but they would have scored more if he wasn't.  He isn't a great one-on one defender, but that has to be a very difficult thing for a relatively short player, guarding people a half-foot taller.

Also where is Kobe on that list, I have to give hm credit for working hard on defense, at least when I saw him play.

[Derek Bodner]

Other teams may have scored on the Sixers when he was in there, but they would have scored more if he wasn't.

AI is a bad man-man defender.  Absolutely terrible at denying penetration, and loses his man on the perimeter.

[Joe Vancil]

Derek,

I disagree.  I think Iverson is a WONDERFUL defender.  I agree that he's not the best at denying penetration.  However, Iverson is a player who plays PASSING LANES.  The idea is to DISRUPT what the offense is trying to do.  And that's the reason he'll lose his man on the perimeter.

Larry Brown turned that into an INCREDIBLE defensive model because he had Eric Snow and George Lynch, who were also great defenders, to use in rotation, and Ratliff/Mutombo to erase mistakes.  And Tyrone Hill was no slouch.  But it was all predicated on Iverson DISRUPTING what the other team was doing.

Iverson still plays the same way...it's just that Snow, Lynch, Ratliff, Mutombo, and Hill are all gone, and Dalembert isn't as dominant a shot-blocker, and Iguodala is an entirely different kind of defender.

There's nothing wrong with Iverson, and I think you'll see that now that you've got a COACH again.  Cheeks will implement a good defensive scheme, and Iverson will look solid again.

 

[Derek Bodner]

I disagree, espeically with the impact his steals have.  More often than not, his gambles result in a 4-5 opportunity for the other team than a steal.  And considering steals are the ONLY positive attribute he has going for him defensively, it doesn't make up for all he DOESN'T do.

Yes, in the right system, with dominant team defenders at every other position he's an attribute defensively.  Without that, he's a serious liability.

[Guest_Randy]

AI plays the passing lanes VERY well but with a great defensive scheme, you can have a player that isn't a great defender.  A good example of that is the Spurs -- Parker isn't a great defender and Billups was burning him badly -- but Pop makes an adjustment in his defensive scheme and Billups is stopped cold (and Pop didn't make that adjustment until halftime so that Brown couldn't prepare for that change -- GREAT adjustment by Pop).  It's STILL a mystery why the Pistons didn't start going to Prince at that point -- because Manu nor Parker could have guarded prince.

Anyway, when the Sixers went to the Finals, that was a VERY good defensive squad (with the exception of AI) but because of the other defenders, AI was allowed to roam the passing lanes and gamble.  It paid off well for the Sixers the entire year -- however, the Sixers counted on offensive/defensive rebounding too much (esp. second/third shot opportunities) and the Lakers were a better rebounding team (not to mention better defensively).  AI hurt the Lakers in steals but it wasn't enough to overcome the Sixers offensive liabilities.

[SPURSX3]

Shane Battier
Darius Miles
Trevor Ariza
Shandon Anderson

all come before Bruce Bowen?  what a load of crap.  


Paul Pierce, The guy has an overall game and is THE player on his team.  I could see him at the top of the list as he gives himself to the game as much as he can.  but the rest?  come on.  

[Joe Vancil]

Regarding the list:

I cannot believe Matt Harpring is on the worst list.  As a 2-guard, I could understand it, because he can't cover 2-guards.  As a big forward, I could understand it, because he's outsized.  But as a 3?  I don't see anything wrong with his defense.  Not a single thing.

Seeing Shandon Anderson on the best list was somewhat surprising, as well.  I know he's not BAD, but I just don't think he's GOOD.  Then again, I didn't see him much for Miami this past year.

Paul Pierce is somewhat of a surprise, too.  I don't consider him anything special as a defender.  However, I think of him as a 2, not a 3.

Ariza is no surprise.  The guy is simply a great defender.

Nailon and Szczerbiak surprise me.  I think that might be because these guys are 'tweeners - Nailon played some 4 and Szczerbiak is caught between being a 2 and a 3, and which he plays changes from year to year.

2-guard is a tough one for me.  I've got no problem with Iguodala, Wallace, Ginobilli, and Jones, and I don't know enough about Allen, Smith, or Gordon.  McKie?  If you ask me, he's slipping...A LOT.  I wouldn't have mentioned him as a person I consider a great defender.

On the bad side, Bogans is surprising.  I always felt he wasn't a bad defender...I'd have called him "above average."

And then, there's Raja Bell.  When Bell was with Philadelphia and Dallas, I thought he was a good defender.  When he was with Utah, I thought he was okay, but that he had slipped quite a bit...I'd have called him "average."  I think that in Phoenix, he should be a good defender again.  Seeing his name there is surprising.

Tayshaun Prince's absence also surprises me, however, when you consider the sheer number of people I would call "good" defenders at the 3 or the 2/3 swing, it may just be a case of sheer numbers.

Point guards:  AMEN, BROTHER!  Although I am surprised - VERY surprised - that Payton didn't make the "best" list.  The guy is still an AWESOME defender.

I don't know enough about Banks to evaluate him, but I agree with the rating for every other point guard up there!

Interesting article, ziggy.  Thanks for posting it.


 

[Guest_Randy]

There are a LOT of problems with this rating system.  It's a bunch of bunk, IMO.  It doesn't give a true rating and a lot has to do with the quality of the team behind the player, doesn't it?

Shane Battier
Darius Miles
Trevor Ariza
Shandon Anderson

Those guys are defenders?  Anderson can't even BUY his way into the league anymore and Battier isn't a very good defender.  Bowen is one of the best stoppers in the league -- just ask Ray Allen  :rofl:  :rofl:  :rofl: .

There isn't a very good formula for determining defensive prowess -- you can tell what players are great defenders based upon the job that they do night in and night out.  Players that can shut down other players and keep them below their average -- and I'm talking BY THEMSELVES -- not with a good double or triple-team.  

How many shooting guards can shut down (keeping them 10 points below their scoring average) TMac, for example, by themselves?  That's how you determine what kind of defender you are -- this formula is a bunch of crap and doesn't show reality!

[Joe Vancil]

Ariza should ABSOLUTELY come before Bowen.  And if Battier is behind him, he's not far behind him.

Miles and Anderson, though?  I think you're right.  Bowen's better than either of those guys defensively.
 

[Derek Bodner]

all come before Bruce Bowen? what a load of crap.

If you would have RTFA (sorry, /. reference) you would have noted that the author says there is really no validity in differentiating between the top and the bottom.  And I quote:

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.

Those guys are defenders?

Yes, and very good ones.  If you don't know Ariza and Allen, you will.  Shandon Anderson is an above average perimeter defender, it's the only reason he was, and still will be, in the league.  Shane Battier is a very good overall defender, I'm not sure why you're surprised he's on the list.

Joe: I was never in love with Harpring's defense in Philly.  Hustler?  Sure.  Solid team defender?  Ok.  Poor man-man defender?  IMO, yes.  And it just got worse playing out of position for a little bit last year and coming off an injury.

McKie, IMO, was the Sixers second best defender last year.  I saw a completely difference on that end of the court when he was in the game last year.  Best hands on the team, I've never seen a guy able to pick another man clean without ever being out of position if he misses like Aaron does.  Where Aaron's marked decline has come is in the offensive side of the ball.  While he was never overly assertive offensively, he's completely made himself into a non-threat (even though he can still shoot the ball).  And while he used to be a capable pg, he now gets his pocket picked clean.

[JoMal]

In other words, team defense impacts how each player gets ranked, instead of straight on defense of the player. A guy can be ranked much lower using this scale then he might otherwise be if he plays in a system like, say, Sacramento's, where team defense is always the other guys job.

Stojakovich is considered one of the better King defenders, not that that is saying much, but he certainly gets no help from anyone else if his man beats him.
 

[ziggy]

There are a LOT of problems with this rating system.  It's a bunch of bunk, IMO.  It doesn't give a true rating and a lot has to do with the quality of the team behind the player, doesn't it?

How many shooting guards can shut down (keeping them 10 points below their scoring average) TMac, for example, by themselves?  That's how you determine what kind of defender you are -- this formula is a bunch of crap and doesn't show reality!

Thats right Randy, don't confuse the issue with facts, lets focus on opinions.

Simply it is +/- when the player is on the floor, and then it is adjusted based upon who else is on the floor with you.  Who you are playing with is equalized out (as much as possible).  If your +/- gets worse when you play with poor defenders, but increases when you are not playing with them, then your defensive score is adjusted to measure that effect.  That is specifically what it is trying to do.

If a defender could shut down a Tracy McGrady, and hold him to 10 points below his average, then logic holds that Houston would score fewer points.  If that is the case then the +/- would increase for the team facing McGrady.  The +/- would be greater when that player is on the floor, since he is the one shutting down McGrady.  If that was the case then that player would have a very large +/- differential and he would rate much higher on the rankings.
If on the other hand the reason McGrady's scoring was down was because of the overall team defense, and his scoring rate was the same no matter who was guarding him, then the effect of that one player would be discounted.

Iverson is a good example of this.  He gets a lot of steals, but steals are not measured in this.  If his steals lead to more points, than the points allowed off his blown steals then he will get a higher defensive rating.  The impact of the Eric Snow's and the George Lynch's is factored in.  If they help cover for his mistakes, they get credit for it, but Iverson doesn't get excess credit for creating a stat, the steal.

[SPURSX3]

all come before Bruce Bowen? what a load of crap.

If you would have RTFA (sorry, /. reference) you would have noted that the author says there is really no validity in differentiating between the top and the bottom.  And I quote:

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.

Those guys are defenders?

Yes, and very good ones.  If you don't know Ariza and Allen, you will.  Shandon Anderson is an above average perimeter defender, it's the only reason he was, and still will be, in the league.  Shane Battier is a very good overall defender, I'm not sure why you're surprised he's on the list.

Joe: I was never in love with Harpring's defense in Philly.  Hustler?  Sure.  Solid team defender?  Ok.  Poor man-man defender?  IMO, yes.  And it just got worse playing out of position for a little bit last year and coming off an injury.

McKie, IMO, was the Sixers second best defender last year.  I saw a completely difference on that end of the court when he was in the game last year.  Best hands on the team, I've never seen a guy able to pick another man clean without ever being out of position if he misses like Aaron does.  Where Aaron's marked decline has come is in the offensive side of the ball.  While he was never overly assertive offensively, he's completely made himself into a non-threat (even though he can still shoot the ball).  And while he used to be a capable pg, he now gets his pocket picked clean.

I READ the article D, IMO it is still a load of crap.