The Assistant Coaches Choose the Best?

Posted on February 13, 2008 by


The All-Star game starters are chosen by the fans.  The All-Star reserves are chosen by the coaches.  And the assistant coaches get to choose the T-Mobile Rookie Challenge rosters. 

Previously I looked at the choices of the fans and coaches in terms of Wins Produced.  Today I am going to offer my review of the choices made by the assistant coaches.

Evaluating the Rookie-Sophomore Rosters

When we look at the rosters in the Rookie Challenge game it’s important to ask: What are the criteria for selecting these players?  Are these players supposed to be the “best”?  How exactly is “best” defined?

Although I am not sure how the assistant coaches defined the term, if we define “best” in terms of “most productive”, we see that a few players fall short of this particular definition.

Table One:  The Rosters in the Rookie Challenge

For the rookies, Al Horford, Sean Williams, Mike Conley, and Jamario Moon look like they belong in this game. Each of these rookies posted a WP48 [Wins Produced per 48 minutes] that was above the average mark of 0.100. But Yi Jianlian, Kevin Durant, and Jeff Green appear to be odd choices. The productivity of these players falls into the negative range.

For the sophomores, the quantity of quality players was higher.  Ronnie Brewer, Rajon Rondo, Brandon Roy, Jordan Farmer, and Paul Millsap are all above average this year.   Daniel Gibson, Rudy Gay, and LeMarcus Aldridge are not above average, but are clearly in the positive range. If the sophomore roster stopped at this point, the average WP48 would be 0.125. This would be consistent with a 51 win NBA team.

Unfortunately for the sophomores, the assistant coaches decided to add Andrea Bargnani to the team. Across the first half of the 2007-08 season, Bargnani was the least productive player in the league.  His addition reduces the average WP48 to 0.088, a mark consistent with a 36 win NBA team. 

With Bargnani on the team, the edge the sophomores should enjoy over the rookies is greatly reduced.  Certainly the sophomores should be favored, but the margin is not quite what it was last year. 

This analysis leads to three additional questions:

1. Who else could the assistant coaches chosen?

2. Do you need Wins Produced to make your selections?

3. Are the sophomores always favored in this game?

Who Else?

To answer the first question, let’s turn to Tables Two and Three.

Table Two: The Rookies at the Midpoint

Table Three: The Sophomores at the Midpoint

When we look at the rookies, the most glaring oversight is Joakim Noah.  Noah leads all rookies and sophomores in WP48.  Of course, Noah also yells at assistant coaches.  So that probably didn’t help him get on this team.

When we look at the sophomores, Josh Boone and Kyle Lowry certainly could have expected a call.  The omission of Boone is especially interesting.  Boone is above average.  He has also played nearly as many minutes as Bargnani.  Yet Bargnani is going and Boone is staying home.

Making the Selection

Why was Bargnani chosen over Boone?  One suspects two forces at work.  First better scorers are probably chosen first.  And by “better”, I mean players with a higher scoring average per game.  Bargnani averaged 8.7 points per game across the first half of the season.  Boone’s average was only 6.9. 

In addition, Bargnani was the first overall choice in the 2006 draft. Boone lasted until the 23rd pick.  It’s possible that the assistant coaches were still influenced by the initial assessment of the players.  Of course, a year and a half has passed since the 2006 draft, so one might think that draft position should stop playing a role in evaluating players [although readers of a 1999 paper by Colin F. Camerer and Roberto A. Weber (“The Econometrics and Behavioral Economics of Escalation of Commitment: A Re-Examination of Staw and Hoang’s NBA Data.” Journal of Economic Behavior and Organization, 39, 59-82) would suspect otherwise].

When we turn to the individual statistics, we have plenty of reasons to think the evaluation of Bargnani would have changed since the summer of 2007.  Specifically, consider Table Four.

Table Four: Durant, Bargnani, and Morrison

Table Four presents that mid-season performance of Durant and Bargnani. For comparison sakes, the performance of Adam Morrison – a player selected to the 2007 Rookie Challenge game – is also included.

The individual statistics for each of these players paint a clear picture.  Durant is below average with respect to shooting efficiency, steals, turnovers, and assists.  Bargnani comes up short with respect to shooting efficiency, points scored, rebounds, steals, blocked shots, assists, and personal fouls.  And Morrison was below average with respect to everything except field goal attempts, turnovers, and personal fouls. In sum, the individual statistics suggest all three players should not be counted among the “best”.

When we turn to Win Score, we see the same story told by the individual statistics and Wins Produced.  All three players did not play well prior to being selected by the assistant coaches.  Again, all three could score (relative to other rookies and sophomores).  And all three were very high draft choices.  Still, each was far below average and should not be rewarded for what they have done thus far in the NBA.

Are the Sophomores Always Better?

I am going to end this column with a brief comment on the sophomore’s record in this game.  Currently the second-year players have a five game winning streak and have won six of the eight challenges held.  This should not surprise, since an average rookie posts a WP48 of 0.047 while an average sophomore has a mark of 0.076.  In sum, sophomores tend to be better than rookies.

Last year the sophomores were quite a bit better and the game was a blow-out.  This year, as noted, the teams are closer.   At least, they are closer as long as Bargnani plays and fails to produce.  If somehow Bargnani can stay on the bench, or better yet, if he starts playing like a number draft pick, the sophomores should again cruise to victory.  At least, they would cruise if our sample was greater than one.  With such a sample, anything could indeed happen (although I still suspect the sophomores will win).

 – DJ

Our research on the NBA was summarized HERE.

The Technical Notes at provides substantially more information on the published research behind Wins Produced and Win Score

Wins Produced, Win Score, and PAWSmin are also discussed in the following posts:

Simple Models of Player Performance

Wins Produced vs. Win Score

What Wins Produced Says and What It Does Not Say

Introducing PAWSmin — and a Defense of Box Score Statistics

Finally, A Guide to Evaluating Models contains useful hints on how to interpret and evaluate statistical models.