Why The Mavs Are The League's Deepest Team - And Why That May Be A Problem

[Pirate]

Originally Posted by Five-ofan

No they dont but the fact that the suns with diaw on the court are better than the mavs with howard on the court does go a long way and that isnt plus minus.

Not really. All they say is the whole group is better.

[Five-ofan]

Then how does the whole group get so much worse the instant he goes off the court and better when howard goes off?

[Pirate]

5-0.... Because its not a move in a vacuum and it isnt using the same standard to measure both players. It the SWAP we are getting information about. Let me go back to my prior illustration, because it's apparent you still fail to grasp the implications, and lay it out a bit more colorfully.

Imagine a world where we can put a radar-like gun on an NBA player, like they do the radar gun on pitches, and measure the Defense Ability they have. That of course would give the definitive answer to this topic of how good they are defensively.

I am going to create my own and pretend it exists.

Now we have the numbers you gave above. Diaw goes out of the game and Phx sags defensively. He goes back in and they improve. So we surmise that he is a good defender and probably one of their better ones.

Then we zap the gun on each Phoenix defender.
A - 9
B - 8
C - 7
D - 6
Diaw - 5
Whoops, we now see that he is actually the worst defender they have! But why does the team defense go down when he leave? We zap the replacement - and get a 1. Ohhhhhhh.

But wait. Look over there. There are the Mavs. Everytime JHo goes out of the game, they get better defensively. When he comes in, they get worse. Surely this proves Diaw is at least better than Jho doesnt it? So we trot out our trusty gun.
A - 9
B - 7
C - 6
D - 5
JHo - 8
Whoops. We see that Jho is actually one of the better defenders on the Mavs. And we see that Diaw is nowhere near as good defensively. But wait, why was the team better when Jho goes off the floor? We find his backup, zap, and get 9. Ahhhhhhhhhhhhhh.

Thats the problem with plus/minus. You arent comparing players on differing teams to each other or to an objective and identical STANDARD. You are comparing them to their backup (only). And since the backup from team to team can (and does) differ greatly, then it skews the whole plus/minus when it is misused in comparing players between teams (and even players on the same team who play different positions).

[grndmstr_c]

Gosh, it's too bad there's no way to actuallly look at the Phoenix and Dallas rosters to see whether or not all of Diaw's backups are actually srubs and all of Josh's backups are actually badasses...

...oh yeah, that's right, there is a way. See, what we can do is GO LOOK AT THE FREAKING ROSTERS! Just because you can envision a hypothetical scenario in which the net +/- would be misleading doesn't mean that scenario even comes close to accurately capturing the truth, which, as I've pointed out to you twice, it doesn't.

Maybe the third time is the charm. Screw the hypotheticals, here's the facts. What follows is a breakdown of the percentage of time that the Suns' (arguably) three top defenders were on the court in Diaw's on-court as compared to off-court minutes (higher on-court % would be consistent with Pirate's hypothetical scenario, higher or equivalent off-court % would be inconsistent with Pirate's hypothetical scenario):
Bell: on-court % = 73%; off-court % = 76%
Marion: on-court % = 81%; off-court % = 86%
KT: on-court % = 29%; off-court % = 52%

So what does that mean? Simple, it means that the minute distributions of the player pairings between Diaw and the Suns (arguably) top three defensive players actually point to a conclusion that is EXACTLY THE OPPOSITE of this hypothetical BS that Pirate keeps spewing. Far from inflating Diaw's defensive +/-, those numbers suggest that Diaw's defensive prowess is being UNDERESTIMATED by his defensive net +/-.

I've got to go to class. Maybe when I get back home I'll break down the numbers for Josh as well, but if what I just posted doesn't put these inane objections to the +/- methodology to rest then I'm skeptical it's even worth trying any further. There's just no knocking sense into some people.

[V2M]

Pirate, yes I got your point. You don't care whether Josh is better or worse than Diaw. You're just trying to prove that the +/- stats by themselves don't conclusively prove anything... unless , of course, if we take into consideration the stats of the guys who are replacing these two.

And, I believe, we all agree with that. Our point is that the delta between the two replacements (Stack/Grif and KT/Jones) couldn't possibly be so high as to erase the original, high point difference.

Good discussion... thanks! I learnt a couple new stuff!!

[Pirate]

V2M ."Pirate, yes I got your point. You don't care whether Josh is better or worse than Diaw. You're just trying to prove that the +/- stats by themselves don't conclusively prove anything... "

Correct.

All that was being offered here when I spoke up was "the plus/minus PROVES _________" and it did no such thing. I was not and am not saying it cant be figured out, but a blind use of raw plus/minus is really a total misapplication of stats for this thesis.

[Pirate]

GC ...Ohhhhhhhh, you mean you are FINALLY offering stats that matter, rather than just taking potshots at me for criticizing the use of stats that in the form they were offered had no reliability whatsoever? Well congrats, you crotchety old coot. It's about time!

[chumdawg]

Only KT would have any significance at all, according to the stats GMC just posted. 73/76 and 81/86 are not significant splits.

I would think that you would have a hard time comparing the respective players' defensive prowess at all, given the marked disparity in the styles their teams run. The Mavs run a style where a stud defensive swingman would have the stats to show it. He's got a strong defensive frontline behind him. His team tries to slow the pace, relatively speaking.

The Suns, on the other hand, as a team do not place a huge priority on shutting the opponents down. If the question is who would be a better defender on the Mavericks, Howard or Diaw, that's one thing. If the question is who would be a better defender on the Suns, it's quite another thing.

I personally think that Diaw would be a better defender in both scenarios. He has physical gifts that exceed those of Howard.

[StackAttack]

Ha. Sorry for the bump, but I just read through some of this thread and chuckled a bit at some of my predictions and the fact that most people agreed with them. I can't believe I ever spoke so highly of Maurice Ager.