Part Two of a Q&A at Valley of the Suns (and a discussion of conventional wisdom and advanced statistics)

Posted on July 27, 2010 by


The second part of my Q&A with Michael Schwartz (of Valley of the Suns) has now been posted.  In part two, we discussed

  • why the Suns were wise to allow Amare Stoudemire to depart.
  • how the Suns might be able to overcome the loss of Stoudemire.

At the very end of the discussion, I note that Suns will probably make the playoffs in 2011 and Amare will probably be sitting at home.  Upon further review, I still think the Suns are a playoff contender.  But I am not sure about the Knicks.  At least, I think it is possible the Knicks can contend for a final playoff spot in the East.

Although our discussion focused on the Phoenix Suns – and one presumes that the readers at Valley of the Suns are interested in that topic – the comments seemed to focus on a different topic.  In discussing the value of Amare Stoudemire, I noted the Top 30 players according to Wins Produced in 2009-10.  This list – judging by the comments – made some people unhappy.  Specifically (and this was surprising since this was a website devoted to the Suns), people were unhappy that Kobe Bryant – who produced 9.9 wins and ranked 32nd in the league last year – was not on the list of Top 30 players. 

Here is one comment that captures the general theme: “I don’t know what’s worse: saying Lamar Odom is better than Kobe or saying David Lee is the 11th best player in the league. C’mon Schwartz, if you’re going to do advanced stats, you might as well use the ones that make sense.” 

Although I prefer Wins Produced (for reasons I have stated many times in the past), one should note that Win Shares (at Basketball-Reference) lists David Lee as the 12th most productive player in the league (ahead of Kobe).  Adjusted plus-minus (a model that I think has some significant problems) does place Kobe ahead of Lee and Odom.  But it also says Matt Bonner is the 12th most productive player in the game (ahead of Tim Duncan). 

As I noted back in 2007, all of the “advanced” statistical models (well, maybe not the Player Efficiency Rating) create rankings of players that defy conventional wisdom.  That’s because conventional wisdom is driven by points scored.  And the “advanced models” are not driven by scoring (well, except for the Player Efficiency Rating).  So if you are an adherent to the conventional wisdom of the NBA, you are probably never going to like any of the advanced models.

And that means fans of the NBA have a choice.  They can simply follow the conventional wisdom.  That means you look at a player’s scoring and believe that Allen Iverson, Carmelo Anthony, Rudy Gay, etc… are above average (if not absolutely great) players.  Of course, when your team gets these players you may not see as many wins as you like.  But then you can turn to the subject of chemistry (or fairy dust, astrology, etc…) and still remain pretty happy.

If that approach doesn’t work for you, there are a few advanced statistical models you can examine.  Of course, there is a problem with this approach.  More than one model has been offered.  How do you decide which model is the “best”? 

Well, the first step is to spend some time trying to figure out how each model is constructed.  That means you should spend some time reading Mathletics (by Wayne Winston, who explains adjusted plus-minus) and Basketball on Paper (by Dean Oliver, who provided the analysis that serves as the basis of Win Shares).  And for Wins Produced, you should spend some time reading Stumbling on Wins (and reviewing material at and in this forum).

Once you understand how the models are constructed then you have to think about how models should be evaluated.  Some time ago I offered A Guide to Evaluating Models. There is also some discussion of model evaluation in Stumbling on Wins.  And I have a chapter in a forthcoming sports economics collection that comments on this subject.   Obviously I think each of these works will help.  But whether you agree or not, it is clear that you will have to do some thinking if you choose to look at “advanced” models.

So the advanced models can provide a better way to look at basketball (for whatever that’s worth).  But they do come with a cost (i.e. you have to do some thinking to appreciate how these models work).  And this is why I think we are unlikely to see a day when most NBA fans abandon the “conventional” wisdom.

– DJ

P.S.  Let me offer a pre-emptive comment. There are those who claim: “I don’t adhere to any model. I look at everything because all models are useful.”  I find this approach to be less than convincing. At the end of the day, you still need to have some criteria in evaluating any model.  If your criteria tells you that all models are useful, then I think you need to re-think your process.  Although I am not sure there is one “best” model (for example, Ty Willihnganz offers a very interesting variation on Wins Produced at Courtside Analyst), I do think there are models that are better than others.  And if you are looking at the models that are not as good, I am not sure you are making a good use of your time (again, for whatever that is worth).