Last summer everyone “knew” that John Wall was the obvious player for the Wizards to select with the first pick in the NBA draft. Well, everyone not looking in this forum.  In this forum (and at Arturo’s Amazing Stats), an issue was raised about John Wall. And here is how the issue was phrased:

Now it’s very important to emphasize what I am saying.  I am not saying – and I repeat, I am not saying – that Wall will never be a great basketball player.  What I am saying is that in college and summer league he was not a great basketball player (again, I am differentiating what Wall has done from what he might do in the future).

We have now moved further into the future (relative to where we were last summer).  So what does Wall look like 64 games into his rookie season?

APM Tells Us John Wall (and Kobe Bryant) are Very Bad

To answer this question, let’s refer to a model that Slate.com recently told us that “many NBA stats experts use as part of their player evaluation system.”  No, I am not talking about Wins Produced.  Nor am I talking about Player Efficiency Rating (although Slate.com told us that teams use this method as well).  What I am talking about is Adjusted Plus-Minus (APM).

According to APM numbers reported at Basketball-Value.com, John Wall hasn’t just had a difficult rookie season.  John Wall – again, according to APM – is actually the least productive player employed by the Wizards.  Yes, you read that correctly.  Wall is the least productive player on a team that has only won 16 games this year.  And let me add that when you look at the Cleveland Cavaliers and Sacramento Kings – the only two teams that are actually worse than the Wizards this season – there is not a single player on either team offering less than Wall. 

When you look at the entire league, you see eight players in the NBA who have a lower APM than Wall.  Apparently – according to APM – Wall has been an incredibly poor choice.

Now some people might object to this analysis.  Certainly when I suggested that Wall may not be a great player, there was quite an uproar.  And all I did was suggest a possibility.  I never said Wall was definitely not going to be a great NBA player.  The APM model, though, is clearly telling us that so far, Wall has definitely not been a very good NBA player.  In fact – according to APM – Wall is one of the worst players in the NBA.

So where is the uproar?  And where is the uproar when APM argues that Kobe Bryant is well below average?  Or Ray Allen, Kevin Martin, or Al Jefferson?  Yes, these players are also well below average this season according to APM.  But as far as I can tell (and maybe I am just not looking in the right places), I don’t see too many people upset with the idea that a model NBA teams are paying money to employ arguing that John Wall and Kobe Bryant are two of the worst players in the league (and this seems odd since I have occasionally heard quite an uproar over what Wins Produced says about Allen Iverson, Carmelo Anthony, Derrick Rose, Ben Wallace, Dennis Rodman, etc… ).

The APM Evaluation Again

Of course, one can’t evaluate a model by looking at whether it conforms to our non-statistical beliefs.  In fact, it is clear the NBA doesn’t take this approach.  In other words, if the NBA thought their non-statistical approach was good enough they wouldn’t bother hiring statistical consultants.  No, the way to evaluate APM is to consider the following (all of which was noted a few days ago):

• The estimated APM coefficients are often not statistically significant.  So for most players, the correct interpretation of the results is that the player in question does not have a statistically significant impact on outcomes.  In other words, it isn’t the case that Kobe Bryant is really a poor player this year.  What we can actually say about Kobe from the APM results is that Kobe’s impact is not statistically significant.  And this is the same story for most players. 
• APM people will note that if you add more years, standard errors will fall.  But we need to remember that the size of a data set and the standard errors are inversely related.  In other words, for any regression, more data will lead to lower standard errors.  One would also note that for APM estimates across five years, it is still the case that many players are not found to have a statistically significant impact on outcomes.
• APM results are very inconsistent over time.  So a decision-maker cannot look at past values and use these for decisions about the future (of course, all decisions are about the future).  This is especially true for players who switch teams.  And that means, APM results for players on different teams isn’t telling you much about what that player will do for your team.
• The model itself doesn’t really appear to explain outcomes.  As Arturo Galletti noted, the initial model (i.e. the model where – in the words of someone selling this model to an NBA team – “the effects of the other players on the floor are accounted for”) explains less than 5% of outcomes.  This point was never noted by the APM people in the past (at least, it isn’t mentioned HERE). 

Mosi Platt – of the Miami Heat Index – discussed the APM issue a few days ago and wondered by the statisticians the NBA has hired weren’t able to note the problems with this model.   My sense is that when an APM person is hired by an NBA team, that person becomes the “stats department” for that team.  In other words, there isn’t an independent group evaluating models for the NBA.

If this is true (and I can’t say for certain), one wonders if people in the NBA were told about the issues with APM before they purchased the product.  Were they told…

• the model where we attempt to control for teammates explains less than 5% of outcomes.
• most of the results from the model are statistically insignificant, and that means APM cannot tell you if most players had any statistically significant impact on outcomes.
• the results from the model are very inconsistent across time.  Specifically (see the FAQ page for this point): “…as Berri and Bradbury (2010) noted, an examination of 239 players revealed that only 7% of the variation in a player’s adjusted plus–minus value in 2008-09 was explained by what he did in 2007-08.”

If the NBA teams who purchased this model were told all this, and then still decided to pay money for the model, then that might be fine. But if this information was withheld from the buyers of the model, then there might be some problems. 

We do know that APM people have been quite critical of box score methods in the past.  And some (but not all), have been very critical of Wins Produced.   But as is often noted, a team’s offensive efficiency and defensive efficiency (from these we derive ADJ P48 and Wins Produced) explain outcomes in the NBA (the same cannot be said for PER – a model, once again, that Slate.com says NBA teams also use).  And unlike APM, ADJ P48 is quite consistent across time.   

In other words, it is possible to use the box score numbers and create a model that both explains outcomes and is consistent over time.  And that means the APM model appears to be a solution in search of a problem.  Or to put it simply, not only is the APM model not very helpful, it isn’t clear the APM model is really necessary.

Back to John Wall

Okay, if APM isn’t necessary, how are we going to evaluate John Wall? Well, how about we just look at Wins Produced.

Here is what John Wall and the Wizards look like – in terms of Wins Produced — after 64 games:

As noted, the Wizards have only won 16 games.  If we look at last year’s performances, we would have expected the Wizards to have only won about 10 games.  So as bad as the Wizards have been, they are a little bit better than last year’s numbers suggest.  And this is primarily because Nick Young has progressed from “awful” to “just bad” while Javale McGee has progressed from “below average” to “above average”. 

McGee is progressed so far that he is now the most productive player on the Wizards.  Unfortunately that isn’t saying much. McGee’s WP48 [Wins Produced per 48 minutes] is only 0.154.  And if that is your best player (a point similar to something I made about five years ago), then your team is not likely to be very good. 

A relatively poor “most productive” player is not the only problem afflicting the Wizards.  The team also doesn’t employ very many above average players (average WP48 is 0.100).  Of the players who have played more than 200 minutes, only John Wall, Rashard Lewis, and Trevor Booker have been above average.  And that tell us…

• contrary to the APM story, it appears John Wall has been slightly above average (you could also say ”about average”).
• in terms of WP48, Booker has done more than Wall.  So Wall isn’t even the most productive rookie on the Wizards.

So let the outrage begin!!  Wins Produced says Wall isn’t the most productive rookie on the Wizards.

Once again… that doesn’t mean that Wall will never be any good.  It just means that so far he has been about average.  If that makes you unhappy… well, at least I am not saying Wall is one of the worst players in the game. 

- DJ

P.S. So why don’t teams use Wins Produced?  Well, I have spoken to NBA teams in the past.  For the last team that called me, though, I told them to simply go buy the Wages of Wins.  More specifically, I told them that an intern could calculate Wins Produced.  So there was no need to hire me.  Yes, apparently I need to work on my “pitch” to NBA teams J

If it’s the weekend, it’s time for another Wages of Wins Network podcast. 

On Friday the cast was as follows:

• Mosi Platt from the Miami Heat Index
• Devin Dignam from Nbeh?
• Arturo Galletti from Arturo’s Amazing Stats
• and me (from this forum)

And here are the topics (and corresponding links) we discussed:

Small Markets vs. Super Teams

• Dre Alvarez on the history behind such moves
• David Stern seems okay with stars moving out of small markets (and I am not sure we disagreed)
• For more on the competitive balance and the short supply of tall people, see The Wages of Wins [or this post from 2008].

March Madness and the NBA Draft

• Ty Willihnganz had two great posts recently on the NBA Draft.  First is a post on the weak correlation between scoring in college and the NBA.  Then he looked back on the 2010 lottery picks.  Both note how hard it is to forecast from college to the pros in the NBA (although not as hard as it appears to be in the NFL). 
• In addition, we discussed the benefit of trying to improve draft position by losing games (an issue discussed by Devin -  in Champions and Drafted Players — and in this forum HERE). 

Arturo has also written extensively on this topic.  Here are some of his posts on the NBA Draft.

• Value of a Draft Pick and Changing Value in the NBA draft
• Ranking Thirty Years of Draft Picks
• and the very important: Build me a Winner (rev. 1.1)

We also discussed the 2011 draft.  DraftExpress reports each player’s Win Score. In evaluating these Win Score numbers, keep in mind the average performance at each position (average of player drafted out of college in recent seasons):

• Point Guard: 7.40
• Shooting Guard: 8.40
• Small Forward: 9.95
• Power Forward: 12.59
• Center: 12.32

As one can see, Kenneth Faried is well above average (at whatever position he plays).

Our last topic of conversation was the NFL labor dispute. 

This discussion began with an article written in the Washington Post (which quotes some professor from Southern Utah University).  It is my hope to write more on this topic in the next few days.

- DJ

Here are two non-controversial statements:

• LaMarcus Aldridge did not play well enough to be an All-Star his first three years in the league [2006-07 to 2008-09].
• LaMarcus Aldridge did not play well enough to be an All-Star in 2009-10.

This past week, though, LeBron James called LaMarcus Aldridge the “biggest snub in All-Star history.”

So what’s changed?

In 2009-10 – when I think most people didn’t think Aldridge was an All-Star – Aldridge averaged 17.9 points per game.  This mark ranked 31^st in the NBA.

This season he ranks 14^th in scoring per game with 22.4 points per game.  

Could it be that this is all that has changed? Let’s look at all the numbers.

The table above compares Aldridge to an average power forward.  As one can see, Aldridge is slightly above average with respect to shooting efficiency and somewhat below average with respect to rebounding and assists.  Prior to this year, he was also below average with respect to getting to the free throw line and steals (for the latter he is now just average).

When we compare 20o9-10 to 2010-11, we see a small improvement in shooting efficiency from the field and the line; as well as an improved ability to get to the free throw line.  Aldridge is also blocking more shots and committing fewer fouls.   When we put all these stats together we see that Aldridge’s WP48 [Wins Produced per 48 minutes] – at the power forward position – has increased from 0.118 to 0.151.

What does this mean?  Aldridge has played 2,552 minutes this season. If he played his entire season at power forward (and he hasn’t), then he would have produced 8.0 wins thus far this season.  What if Aldridge still had a 0.118 WP48?  Then he would have produced 6.3 wins.  So Aldridge’s improvement is only worth 1.7 additional wins (or 2.2 wins over an entire 82 game season).

Of course, LeBron – and others who think Aldridge is an All-Star – are not looked at WP48.  What they are primarily looking at is scoring.  This season, Aldridge has already scored at least 30 points in ten different games.  And he has scored 40 points or more twice.  Last season Aldridge only scored more than 30 points twice; and he never scored more than 32 points in a single game.  So Aldridge is clearly scoring more.

But that is primarily because he is taking more shots from the field.  As we have seen with Carmelo Anthony, Allen Iverson, etc…; just taking more shots doesn’t really help a team win more games.  Shots are primarily taken from teammates.  In the case of Aldridge, one suspects he has benefitted from the injury to Roy.  With Roy missing games, and taking fewer shots when he does play, Aldridge is seeing more shot attempts.  And these additional shot attempts have led to more scoring and more attention from people like LeBron James.  But when we look at all the statistics, we are not seeing many more wins.

Thankfully for the Blazers, LeBron is not the only one who isn’t evaluating NBA talent perfectly.  Michael Jordan believes that Derrick Rose is clearly the MVP this season:

“MVP of the season. He deserves it. He’s playing that well. He deserves it. Without a doubt. And if he doesn’t get it, now he’ll see how I felt a lot of years.”

As noted a couple of weeks ago, Rose – like Aldridge – also benefits from taking more shots.  If Rose took fewer shots, he probably wouldn’t be an MVP candidate (and as noted, the Bulls probably won’t be any worse off with Rose shooting less per game). 

One might suspect that an NBA owner – and past GM of an NBA team – would not be fooled by a player taking more shots.  But Michael Jordan has not exactly shown us that he can identify the most productive players in the game.

For example, consider the Gerald Wallace trade (see, there was a reason for the Derrick Rose detour).  As noted a couple of days ago, the Wallace trade hasn’t really helped the Bobcats.  On the flip side, though, it has helped the Blazers. 

Here is what this entire team looks like after 64 games (remember, Aldridge has spent time at center so his WP48 mark is lower than what was reported above).

The Blazers have won 37 games this far.  The team’s efficiency differential of 0.97 – and corresponding Wins Produced — is consistent with a team that should have won about 34 games.

When we look at performance in 2009-10, though, we see a team that should have won about 43 games.  In other words, the Blazers should have the 4^th best record in the West.  And in terms of efficiency differential, the team’s projected mark of 5.4 would only be topped by the San Antonio Spurs and LA Lakers in the West.  In sum, the Blazers – based on last year’s performance – should be contenders in the West.

When we look at how performance has changed, we can see three players – Brandon Roy, Nicolas Batum, and Dante Cunningham — who are responsible for the Blazers failure to contend.  Roy has been hurt, so it is easy to understand his performance decline. 

As for Batum and Cunningham, the trade for Wallace can help resolve both issues.  Thankfully for the Blazers, Jordan took Cunningham in the trade for Wallace.  So a player who was hurting the team is now playing elsewhere. Furthermore, Wallace and Batum essentially play a similar role.  Batum has averaged more than 30 minutes per game this season, but has played less than 30 minutes per contest across the last three games.  So if Wallace is taking minutes from Batum (not sure that is the case), then this trade also addresses part of the problem with Batum’s lack of production.

So are the Blazers back to being contenders?

With Wallace added to the roster, the team now has above average players at every position:

• PG: Andre Miller [0.206 WP48]
• SG: Rudy Fernandez [0.131 WP48]
• SF: Gerald Wallace [0.247 WP48 in 190 minutes as a Blazer]
• PF: LaMarcus Aldridge [0.151 WP48]
• C: Marcus Camby [0.322 WP48]

The team really doesn’t have much depth behind Camby and Aldridge in the frontcourt (Batum and/or Wallace can play the PF if necessary).  Furthermore, the back-up point guard position isn’t helping (Patrick Mills is the problem here).  And Roy is still hurt.

Still…the Wallace trade clearly helps this team.  And the price seems quite low (some non-lottery first round picks and Joel Przybilla — who is older and not entirely healthy).

So although Aldridge is not quite as good as people believe, the Blazers look like a team that could make some noise in the playoffs.  At least, if they somehow get to draw the Mavericks, they might have a chance.

- DJ

The Carmelo Anthony trade has been frequently discussed from the perspective of the Knicks.  But what about the supposed “losers” in the trade?  How did this trade impact the Denver Nuggets?

When the trade was announced I offered the following “quick” thoughts on the Nuggets.

• Denver really should have insisted on Landry Fields. 
• Replacing Melo with Chandler and/or Gallinari only would cost the Nuggets about two wins this season.  So yes, this is a small step back.  But it appears rather small. 
• Felton offers less than Billups, but again…. Billups is old (34 years old).  Felton gives the Nuggets a player who is a bit less productive, but eight years younger.
• Who is going to play small forward for this team?  The team now has Chandler, Gallinari, and Gary Forbes.  Plus, J.R. Smith and/or Aaron Afflalo appear to have swung to the small forward spot this year.  Not real clear how those minutes get allocated.
• The Nuggets now have three above average big men (Nene Hilario, Chris Andersen, and Kenyon Martin) and three big men who produce in the negative range (Al Harrington, Melvin Ely, and Mozgov).  Interesting to see how those minutes get allocated.

In sum, it is not clear who is going to play for Denver.  It is possible to come up with a line-up where this trade doesn’t really hurt Denver that much. But it is possible for this trade to really hurt, especially if Mozgov – the player they supposedly insisted upon – actually plays.

To summarize, when the trade happened I thought it was possible that Denver would still be about as good.  But since it was unclear how minutes were going to be allocated, it was unclear how this trade was going to impact the team.

Denver has now played seven games since Melo departed.  In those seven games, Denver is 5-2.  The team’s efficiency differential in those seven games is 10.4, a mark consistent with a team that would win more than 65 games across an 82 game season.  With Melo the team’s efficiency differential was only 2.5, a mark consistent with a team that would win about 47 games across an 82 game season.  So clearly, losing Melo has made the Nuggets much, much better.

Okay, it has only been seven games.  We really can’t offer an evaluation of this trade that is based on such a small sample.  But what we can do is see how minutes have been allocated by the Nuggets.   

As noted, we didn’t know how minutes would be allocated before the trade (or at least, I didn’t know).  Now that we can see minutes played, we can go back to what we knew about player performance before the trade and project the impact of this move.  The following table details this analysis.

On the left we have how these players have performed in the seven games since Melo left.  Again, the team has an efficiency differential of 10.4.  So it is not surprising to see WP48 [Wins Produced per 48 minutes] marks that are quite good for many players employed by the Nuggets.  So far, ten players (of the 13 employed) are posting above average marks (average is 0.100) since the trade. And six players are beyond the 0.200 mark.  Obviously if this could be sustained, the Nuggets would be an amazing team.  Once again, though, seven games isn’t much of a sample. 

So let’s examine this trade with the performances of the players in 2010-11 before the trade.  This analysis is presented on the right.  And as one can see, eight of these players were above average before the trade happened.  So Denver has some “good” players. But none of these players exceeded the 0.200 mark (although Nene was close).  So this team, given performance before the trade and the minutes allocation after Melo left town, could expect to be about a 50 win team.  Now before the trade the team was only a 47 win team.  So the Nuggets – with and without Melo – are about the same. 

Of course, that fits the general story that Carmelo Anthony is not really a “star”. Yes, he is an above average player.  But he is not LeBron James (or even close). Again, Melo does score a large number of points.  However – as is often noted – this is because he “takes” a large number of shots. 

And I want to emphasize the word “takes.”  Some people argue that shots are “created”.  But I think that is not the correct way to look at it.  The Nuggets averaged 80.0 field goal attempts before the trade.  The team has averaged 82.9 field goal attempts after the trade.  As we note in Stumbling on Wins, a player’s shot attempts tend to come at the expense of his teammates.  In other words, players tend to “take” shots from their teammates.  And when players like Melo depart, other players get to take those shots.

Let me close with two more observations…

• First, there isn’t much of a link between shot attempts and shooting efficiency (at least, not in the sample of 30 years of player data we looked at in Stumbling on Wins).  Yes, it could be the case that if Nene Hilario suddenly took 30 shots a game he would be less efficient.  But this isn’t what happens when a player like Melo departs.  What happens is every player just takes a few more shots per game.  And I don’t expect small changes in shot attempts to have large impacts on shooting efficiency.
• My final note is about Al Harrington.  This past summer, Harrington was signed by the Nuggets to a $34 million contract.  Entering this season, Harrington had played 23,953 minutes in his NBA career and only produced 6.5 wins.  Yes, Harrington is very far below average.  And at the moment, he is scheduled to be the third highest paid player in Denver in 2011-12.  So I expected Harrington – who has shown the ability to score (because he likes to “take” shots) – would get minutes — and shots — with Melo playing elsewhere.  But so far, that isn’t happen.  Since the trade, Harrington is still very far below average (as he was before the trade).  But he is playing almost ten fewer minutes per game.  So the negative impact of Harrington has been mitigated. 

Once again, I don’t expect what we have seen from the Nuggets after seven games to continue.  But, if Harrington can stay on the bench — and the players who have offered above average production in the past continue to produce — the Nuggets can still be a playoff team.  Again, that is about what they were before Anthony departed.  And that means the Nuggets were not exactly the “loser” in this trade.

- DJ

The Charlotte Bobcats are currently 9^th in the Eastern Conference standings.  And since only eight teams make the playoffs, this means the Bobcats are currently scheduled for a date with some lottery balls in May.

Although the Bobcats would not be in the playoffs if the season ended today, the team is fairly close. The Bobcats are currently only one game out of the 8^th spot.  Given how close this team is to a playoff appearance, one might expect the Bobcats to be doing everything in their power to get better.  But that doesn’t appear to be the case.

About two weeks ago the Bobcats sent Gerald Wallace to the Portland Trail Blazers for two first-round picks (conditional pick from New Orleans this year and a 2013 pick from Portland), Joel Przybilla, and Dante Cunningham.  

What did Wallace mean to the Bobcats?  From 2004-05 (the Bobcats first season) to 2009-10, Wallace produced 70.0 wins and posted a 0.226 WP48 [Wins Produced per 48 minutes].  This season – as the following table indicates – Wallace is again an above average player (average WP48 is 0.100).

In fact, Wallace leads the Bobcats in Wins Produced.  And when we look at the entire cast of players employed in Charlotte this season, Wallace is one of only five players to post a WP48 mark that is above average (average WP48 is 0.100).

Of these five, Derrick Brown was waived on February 24 (to make room for the players brought in at the trade deadline).  Tyrus Thomas has missed most of the season due to injury; but he may return soon and take the place of D.J. White, who has been above average in the 102 minutes he has played this season. 

The other above average player is D.J. Augustin.  Not only has Augustin posted the highest Wins Produced on this team (after Wallace), with Tyrus Thomas hurt (and Derrick Brown off the team), Augustin is the only player left on the roster who has played more than 102 minutes and posted a WP48 mark above 0.100.  And with a mark of 0.110, Augustin is only slightly above average.

With so little production left on the roster, we should not be surprised that the Bobcats have lost five consecutive games by a combined margin of 91 points.  Yes, just when Charlotte should be driving for the playoffs, they are playing some of the worst basketball – from any team in the NBA – we have seen all year. 

Of course, Jordan says that this all part of the plan.

In a brief interview with The Associated Press, Jordan said “I love the trade” that sent the former All-Star Wallace to Portland. While the backup center Przybilla was the only likely rotation player Charlotte got in return, Jordan says it gives his club “flexibility” to make future moves because it acquired two first-round picks and cleared salary-cap space.

“I think it’s one of the best trades,” Jordan said.

Jordan said he’s not content with jockeying for the final playoff spot in the Eastern Conference. He believes the deal puts the franchise in better shape ahead of perhaps a lower payroll ceiling in the next labor deal as he tries to build a contender

“We don’t want to be the seventh or eighth seed,” he said.

Jordan appears to be doing his best to get his wish. Even if Thomas comes back and produces, the Bobcats are going to have a hard time making the playoffs.   And even if the Bobcats make the playoffs, there is little chance this team could advance against the top teams in the East.

So what is the plan?  The Bobcats sent their most productive player to the Blazers for two non-lottery first round picks and two players who don’t have contracts beyond this season.  Jordan says he is going to take this salary cap space and draft picks and go acquire players who can move the Bobcats past the 7^th seed in the Eastern Conference.  Given that this is the person who drafted Kwame Brown and Adam Morrison, this seems like a dubious plan.

Then again, maybe Jordan is simply trying to learn from Mark Cuban.  Cuban recently confessed that once Dirk Nowitzki retires he expects the Mavericks to lose, and, if he gets his way, they’ll lose badly.  In other words, Cuban is arguing that the Mavericks success under his ownership is mostly about Nowitzki (not sure that is entirely true, but the Mavericks success is certainly not – as we just saw this past weekend – about Adjusted Plus-Minus).   So the Cuban plan is to be very, very bad and then hope to build your team through lottery picks and salary cap space.

We should remember that Jordan completed the Wallace trade before Cuban’s comment.  But the thinking seems quite similar.  And the thinking – for fans of the Bobcats – is that Charlotte is better off giving away their most productive player for some chance to acquire productive players in the future. 

Who are these productive players?  We don’t know. 

Will Jordan know these players when he sees them?  The past doesn’t give fans of this team much hope, but that is what fans of this team are being sold. 

Yes, Wallace was traded for a vague hope for tomorrow.  As the Bobcats struggle to win games across the last month of the season, fans of the team should keep this vague hope in mind.

- DJ