## An alternate view on Amare/Antawn Jamison's defense

I wanted to bring cuppettcj's comment in the last Amare Stoudemire thread to the forefront of discussion, since it definitely provides a little more food for thought.  He brought up adjusted plus/minus and mentions how Antawn Jamison actually scores extremely well in that statistic where Amare Stoudemire doesn't.  His comment in full is below the jump.

I have been reading up a lot on adjusted plus/minus recently, the closest thing to a "holy grail" of statistics that we currently have available right now for basketball. If you haven’t read up on it yet, please read the following articles:

Here is a money paragraph from the second article:

This is exactly what the adjusted plus-minus stat does: it reflects the impact of each player on his team’s bottom line (scoring margin), after controlling statistically for the strength of every teammate and every opponent during each minute he’s on the court. Again, the gory mathematical details of the adjusted plus-minus model have been described elsewhere (and they are beyond the scope of this article) – but it’s worth noting that the model relies on the same basic mathematical/ statistical approach currently in widespread use by medical researchers and other scientists all over the world. For example, when an epidemiologist needs to estimate the relative risks posed by smoking, asbestos, and radon and to calculate the odds of contracting cancer on the basis of exposure to each respective hazard, he’ll invariably use the same basic type of statistical model. In other words, the adjusted plus-minus analysis is based upon a robust statistical approach that already provides a solid data analytic foundation for many branches of science and medicine.

Basically, adjusted plus/minus measures a player’s ability to make his team better overall. It takes into account offense and defense. It takes into account the quality of the players playing with that player. It takes into account the quality of the player substituting for that player. It takes into account the quality of the opponents that player faces. It takes into account game pace. It basically takes everything into account in order to isolate that specific player’s contributions to his team’s score per 100 possessions, and then generates that player’s APS number. I would say it seems a lot like PER, only it does a much better job of evaluating and including a player’s defense. Unlike PER, as far as I know, it does not take into account any standard box score statistic, only the minutes played and the effect on the scoreboard after factoring for all of the variables mentioned above.

So who uses adjusted +/-? Well, there have been stories about Mark Cuban paying a handsome sum of money to Wayne Winston and Jeff Sagarin back when the formula was still secret. But now that the formula has been made public by UNC Greensboro economics professor Dan T. Rosenbaum and University of Kansas psychology professor Dr. Steve Ilardi, there is now speculation that the formula is being used by Suns GM Steve Kerr. Consider this exchange:

Ben: Looking at the list, Steve Kerr must be using +/-!

Shaq 9.4

Marion -1.5
Banks -9.7

basketballvalue: Indeed. It is remarkable that despite all the talk of Shaq’s decline, his adjusted /- is high and even his simple +/- is positive as well (6.2). He’s still having a positive impact (22nd by adjusted).

On the other hand, Marion has a strong simple /-(10.5), so it seems he’s effectively getting penalized for playing with good players and often being replaced with good players. Still, it’s a significant adjustment that I’m sure gets into the realm of questionable in some people’s minds.

While APS might explain why Kerr did the Shaq/Marion trade, it also might explain why Kerr may be interested in an Amare/Jamison swap. Check out this list compiled at basketballvalue.com. This list ranks the top 50 players in the league in APS for the past two seasons, double weighting for the playoffs. You’ll notice one of the names on the list is Antawn Jamison, ranking in at #41 in the NBA. Noticeably absent from this list, however, is Amare Stoudemire. In fact, check out this comment over at Bright Side of the Sun:

Hey may drop 40 points

But he’ll give up just as many on the other end.

Using adjusted plus minus, Amare was the SECOND WORST big man defender in the NBA; he’s only ahead of Al Jefferson.

Couple that with his terrible A:TO ratio, and his mediocre rebounding rate….I don’t see why he’s held in such high regard, honestly.

Since one would assume that Amare’s offensive prowess is at least on par with Jamison’s, the only way to explain the huge disparity in APS between the two players is defense. Consider this paragraph from a Wall Street Journal blog detailing Mark Cuban and Wayne Winston’s defense of APS:

Winston, the professor of operations and decision technologies at Indiana University who developed the system for Cuban, said that no system is perfect, but that plus/minus beats other player analyses because it can reflect defensive prowess — and Nowitzki’s defense was subpar at the beginning of the season. It’s with defense, Winston said, that plus/minus "really shines," because defensive stats such as blocked shots, rebounds and steals can’t encapsulate a player’s worth.

So, based on all of this research, I’ve concluded that there is a strong possibility that we are underrating Jamison’s defense as well as his overall value to our team. After all, most of our assessments of Jamison’s defense are purely subjective. We say things like "he doesn’t stay with his man," or "he doesn’t possess lateral quickness," or "he gets backed down too easily." Then we feed these remarks into an echo chamber and the next thing we know everyone is screaming that Jamison is the worst defending power forward in the NBA. Meanwhile, there is objective scientific statistical evidence that says that Al Jefferson is in fact the worst defending PF and Amare is near the bottom, while Jamison is in fact above average at defending. This list was compiled from the 2007-08 season and was found via this article.

In conclusion, I think we may be making a huge mistake in kicking Jamison out the door, despite how much we dislike his comments about our young players. The evidence is starting to convince me that Jamison is much better than we are making him out to be.

For a contrarian viewpoint, be sure to read the Wall Street Journal blog linked to above. There is good debate there between 82games’s Roland Beech and Mark Cuban/Wayne Winston on the merits of APS.

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