Monthly Archives: December 2010

Another Thought on Applying the Studies of Coaching to the Evaluation of Political Leaders

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After posting — Who pays attention to sports economists?  – on Sunday morning I decided that this story would make for a good Huffington Post column. So Sunday evening I re-wrote the story and posted “Should the House Democrats Have Changed Coaches?”.

The primary difference in the two posts is a thought that occurred to me on Sunday afternoon.   Essentially Mark Mellman argued that Nancy Pelosi should keep her leadership position with the House Democrats because – as the research of J.C. Bradbury, my co-authors, and I indicated – leaders don’t have much impact on outcomes.  Therefore Pelosi shouldn’t be blamed for the outcome of the midterm elections.  Although I agree that leaders are blamed too much for failures, it occurred to me that the reverse is also true.  Specifically, leaders shouldn’t get much credit for success.  And if that is the case, what is the argument that Pelosi should keep her leadership position?  Why not just rotate these positions among the available people in Congress? 

As I note, not sure I think rotating these posts is the best way these jobs should be assigned.  But I do think that leaders are given too much blame and credit for the outcomes we observe.

- DJ

Who pays attention to sports economists?

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Sometimes I am surprised at the answer to this question.  To illustrate, a few years ago I was asked by Steve Forbes (okay, actually someone who works for Forbes) if I could send an autographed copy of The Wages of Wins to one of his friends.  More specifically, a copy of The Wages of Wins was sent to me with an envelope and this request.   After complying with the request I never heard from Forbes, his representative, or his friend. And I am still surprised I ever heard from him in the first place.

A more recent example occurred this past week.  Mark Mellman – like Steve Forbes – is involved in politics (although Mellman comes from the opposite end of the political spectrum).  Recently Mellman wrote a column – at The Hill — detailing how the proposed changes to the leadership of the Democratic party would impact outcomes for the party.  Mellman’s argument…

Well, let’s first review the sports economics story.  Let’s start with a recent paper written by J.C. Bradbury.  In “Hired to be Fired: The Publicity Value of Free Agents”, Bradbury looks at how a baseball’s players performance is impacted by a change in managers. 

Of the 134 managers in the sample, the estimates for 25 managers are statistically significant at the ten-percent level for hitters.  21 managers are associated with improvement and four managers are associated with a decline. For pitchers, the estimates for 24 managers are statistically significant at the ten-percent level. 15 managers are associated with player improvement and nine managers are associated with a performance decline. Five managers are associated with improvement and decline for both groups; however, in all cases, the managers are associated with the opposite effect for the two groups of players. Thus, no manager is associated with improving performance for both offense and defense.

In the conclusion, J.C. notes the following:

The results do not mean that managers play no role on baseball clubs. To the contrary, no team could operate without the aid of a manager. Organizing players, settling disputes, and controlling the media are managerial duties that must be handled, and have the potential to be handled poorly. The results of this study indicate that managers who have served at the major-league level do not differ greatly from one another in their ability to handle these important responsibilities in a way that improves or dampens player performance.

Readers of Stumbling on Wins would note that Bradbury’s results for baseball are quite similar to what we reported for the NBA.  The study we review (which I co-authored with Mike Leeds, Eva Marikova Leeds, and Mike Mondello and published in the International Journal of Sport Finance) looked at 62 NBA coaches across thirty years of data.  Across this sample, only 14 coaches were found to have a statistically significant and positive impact on player performance.   So most NBA coaches – like most baseball managers — do not appear to make their players more productive.

Okay, two different studies in sports economics indicate that coaching doesn’t make much difference.  But does this apply beyond sports?

The problem beyond sports is that we don’t have data on worker productivity. So it is hard to see if managers actually make workers better (or worse) in non-sports industries.  Still, I suspect the impact of “leadership” is overstated (especially by leaders).

And Mellman appears to agree.  His column discusses the desire some Democrats have to remove Nancy Pelosi (D-Calif.) from her leadership position in the house.  Mellman – via the arguments offered by J.C., my c0-authors, and I – disagrees.  Here is how the Mellman article concludes:

Fans are seduced by what psychologists call fundamental attribution error — the natural tendency to overweight the personal and underweight the situational in attributing causality. This psychological bias leads fans to believe the problem is the manager, just as experimental subjects believed a model train operator was unskilled when cars kept jumping the track, even after they were told the derailments resulted from a systemic cause — abrupt, random changes in the electrical current to the engine.

Changing managers (or leaders) may make some people feel better because they misunderstand the underlying dynamics, but it won’t cure the problems plaguing the Carolina Panthers, the Pittsburgh Pirates, the L.A. Clippers, the Wolverhampton Wanderers or House Democrats.

One should note that at the end of this article we learn that “Mellman is president of The Mellman Group and has worked for Democratic candidates and causes since 1982. Current clients include the majority leaders of both the House and Senate.”  So Mellman’s analysis might be a bit biased. 

But one suspects –given what we have learned from sports – that the impact of changing leaders is overstated.  In other words, the problems Democrats had in this last election was more about the economy and less about Pelosi.  And when the economy recovers, the opinions people offer about the leadership of Pelosi – and President Barack Obama – will change.

- DJ

A Small Sample in San Antonio Tells A Familiar Story

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Which team is the best team in the Western Conference?  If you guessed the team is in LA, you would be right. On Wednesday night, the LA Clippers defeated the San Antonio Spurs.  And since the Spurs currently lead the Western Conference in efficiency differential (offensive efficiency minus defensive efficiency), and the Clippers just beat the Spurs, the best team must be the Clippers.

Okay, that’s not right.  What is right is that the Spurs – after 18 games in 2010-11 – appear to be approaching the same level of team quality we saw in 2007 (or the last time the Spurs won the title).

That the Spurs are a good team is not surprising.  After four consecutive losing seasons from 1985-85 to 1988-89, the Spurs have had only one losing season since (in 1996-97).  Much of this streak can be tied to the drafting of David Robinson in 1987 and Tim Duncan ten years later.  But unlike other teams that have added amazing talents (see New Orleans with Chris Paul and Minnesota with Kevin Garnett), the Spurs have also been able to find productive players to surround their main star.

To see this point, let’s go back to the last Spurs team to win the NBA title.  The San Antonio Spurs in 2006-07 posted a 9.1 efficiency differential, the best mark in franchise history.  Of the team’s 63.1 Wins Produced (the team only won 58 games), 43.9 could be traced to the play of Tim Duncan, Manu Ginobili, and Tony Parker.  That means everyone else on this title team produced 19.2 wins.

Across the next three seasons, the Spurs appeared to decline.  This can be seen when we consider the team’s efficiency differential from 2007-08 to 2009-10:

  • 2007-08: 5.2 differential
  • 2008-09: 4.1 differential
  • 2009-10: 5.4 differential

It can also be seen when we look at the Wins Produced of Duncan-Ginobili-Parker; as well as the Wins Produced of “everyone else”.

  • 2007-08: Duncan-Ginobili-Parker (41.2 Wins Produced), Everyone Else (12.4 Wins Produced)
  • 2008-09: Duncan-Ginobili-Parker (30.7 Wins Produced), Everyone Else (20.4 Wins Produced)
  • 2009-10: Duncan-Ginobili-Parker (31.7 Wins Produced), Everyone Else (22.8 Wins Produced)

The story in 2007-08 is about “everyone else”.  The team’s trio maintained their production.  But with Brent Barry hurt (the leader of “everyone else”) the production from the supporting cast declined.

The next season the Spurs once again found a quality supporting cast  (led by the play of Matt Bonner and Kurt Thomas).  But with Ginobili hurt, the production from the top three fell.

Last year the team’s supporting cast – led by DeJuan Blair – was even better. And Ginobili was generally healthy.  But with Tony Parker hurt, the team was again unable to return to what we saw in 2006-07.

Entering this season, people looked at the age and injury history of this team and generally concluded that the Spurs had been passed by the Lakers and Heat (not saying everyone thought this, but certainly some people thought this).  But after about 20% of the season has been played, we now see the following:

The team’s Big Three are currently on pace to produce 40.3 wins, or a total similar to what we have seen in the past when this trio is healthy.  The team’s supporting cast – led by Richard Jefferson, George Hill, and Antonio McDyess – are currently on pace to produce 22.8 wins. So “everyone else” appears to be back.  As a consequence, it appears the championship contending Spurs have once again appeared.

When we look at the individual players we do see some additional stories to note.  First, Tony Parker is offering a career high in per-minute production.  Back in 2006-07, Parker posted a 0.185 WP48 [Wins Produced per 48 minutes]. This year – after 18 games – he is posting a 0.191 mark.  So he is better (although not much better than his previous career high).

Richard Jefferson is also offering more. The last time Jefferson was above average was 2005-06.  An injury the next season appeared to permanently reduce the level of production Jefferson offered.  Although he is not back to what we saw in 2005-06 (Jefferson posted a 0.241 WP48 that season), his above average production after 18 games is a good sign for the Spurs.

For those looking for dark clouds, Tim Duncan’s WP48 mark of 0.221 is a career low. Duncan is now 34 years old and at some point he has to offer less.  Is this the season “less” makes an appearance?  Again, only 18 games have been played.  But those games are not a good sign.

And then there is the play of DeJuan Blair, the rookie who posted the highest WP48 mark last season.  This year – again, after 18 games – Blair has been only slightly above average. 

When we look at the individual stats, we see that Blair has had trouble hitting shots this season.   In the last two games, though, Blair has taken 20 shots and hit 11 (for a 55% field goal percentage).  Unfortunately, Blair only hit 4 of the first 20 shots he took this season (across his first three games).  In other words, Blair started the season playing very badly (lately, though, he got better).

What does all that mean?  Well, the Spurs have only played 18 games.  At this point, I think we should focus on who is producing and who is not.  When we start talking about why a player is posting the numbers we see we then run into the problem of small sample sizes.  In other words,  the issues we generally focus upon to explain changes in performance — such as injury (the factor I tend to think matters the most), coaching (sometimes matters), diminishing returns (small impact on per-minute performance), age (matters, but mostly for older players), or less empirical factors (team chemistry or other such stories) — can be seen (or not seen) in larger samples of data.  In small samples of data… well, it is too easy to confuse random fluctuations in the data for something real.

So let me close by simply noting that there is some evidence that the Spurs we have seen in the past (a past where we had an abundance of data) have returned.  The Big Three on this team are offering the level of production we saw in the past.  And it appears the Spurs have once again found a productive supporting cast.  Now if DeJuan Blair starts hitting shots… well 2011 is an odd-number year and we “know” the Spurs like winning titles in odd-number years (okay, we don’t “know” that because, once again, it is a small sample).

- DJ

There is Another “LeBron Story” Taking Place Elsewhere in the NBA

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The big story in the NBA this season has been the Miami Heat.  The expectation was that this team would dominate.  But after 18 games, the Heat’s record stands at 10-8.  So the Heat have currently underwhelmed. 

The Miami Heat Index – one of the blogs in The Wages of Wins network – is doing a wonderful job of covering the problems in Miami.  For example, the post from last Saturday went to great lengths to detail the many problems facing this team.

One of these problems is the play of LeBron James.  By my calculation, LeBron posted a 0.441 WP48 [Wins Produced per 48 minutes] and produced 27.2 wins last season.  This season LeBron is still very good.  But after 18 games, King James is only on pace to produce 15.2 wins (a mark that still leads the Heat) and is posting a 0.236 WP48.  The difference between what LeBron did in 2009-10 and what he is doing this year does much to explain the problems in Miami.

Once again, the Miami Heat Index has this story covered. But I bring it up because I want to note that something similar is happening elsewhere.  Yes, there is another team that is substantially underperforming expectations.  And much of this team’s decline can be tied to a drop-off in the productivity of the team’s star small forward.

What team am I talking about? Obviously I am referring to the Oklahoma City Thunder.

Okay, maybe this isn’t so obvious.  The Thunder currently have a 12-6 record.  And the team’s star small forward – Kevin Durant – leads the NBA in scoring.  So how can this situation be similar to what we are seeing in Miami?

Well, let’s start with the Thunder’s efficiency differential (offensive efficiency minus defensive efficiency).  After 18 games, the Thunder’s mark is 0.2.  Such a differential is consistent with a team that will win about 42 games across an 82 game schedule. Last season the Thunder’s differential was 3.6, which is consistent with a team that wins about 50 games (the team actually won 50 games).  So when we consider efficiency differential, the Thunder have declined by about eight wins.

This decline, though, hasn’t been noticed by many yet.  This is because although the Thunder’s current differential is consistent with a team that would win nine of their first 18 games, the Thunder have actually won 12 games.  In contrast, the Heat’s problems have been magnified because the Heat have only won 10 out of 18 games; when their differential suggests this team should have won around 12 or 13 games. 

The Thunder’s “decline” though appears to be real.  And when we move from efficiency differential to Wins Produced, we can see the source of this problem.

The above table reveals that the Thunder are currently being led in Wins Produced by Russell Westbrook, a player John Hollinger thinks should be considered for MVP in 2011 (insider access required).  Although Westbrook has been good, there are few players who have done more in the NBA (Chris Paul is one name that obviously leaps to mind).  None of those players, though, are on the Thunder.

Last season the Thunder were led by Kevin Durant.  Durantula, though, has decline with respect to shooting efficiency, rebounds, steals, and free throw attempts.  He is also offering more turnovers.  As a consequence, Durant’s WP48 has declined from 0.292 last season to only 0.102 after 18 games this season.  In other words, Durant has transformed from a superstar to a player who is essentially average (average WP48 is 0.100).  As a result, Durant is on pace to offer 11.1 wins fewer than he produced in 2009-10.  

Although Durant has clearly decline, this drop-off has been mostly unnoticed (well, Hollinger noticed the decline in shooting efficiency in the same column declaring Westbrook an MVP candidate).  Certainly the volumes written on LeBron and the Heat dwarf what has been said about Durant and the Thunder.  And I think that difference is at least partially driven by

  • Thunder’s relative good luck (i.e. a won-loss record that exceeds what the team’s differential suggests).
  • the fact Durant leads the NBA in scoring.

If Durant doesn’t return to form, though, eventually the losses on this team will happen with more frequency.  And then – scoring title or not – the high hopes fans of this team has at the start of this season will be dashed. Of course, if Durant does return to form…well, then we will probably never hear much about this story (except briefly in this forum).

Just noting a change in performance is often not good enough for many people.  What people demand is an explanation.  So let me close with my explanation for why Kevin Durant and LeBron have both declined. 

LeBron entered the league in 2003 when Durant was 15 years old.  I suspect — given this age when LeBron became a star — that Durant was a fan of King James.  In fact, I think he is such a fan that he cannot imagine offering a greater level of production than his hero.  So when Durant observed LeBron struggling, he deliberately began making mistakes (in fact, Hollinger noted the air balls Durant has recently launched). 

And I think LeBron has noticed this, and this is why he is offering less.  Yes, this is like the seen in the King and I (am I dating myself with this reference?) where the king kept lowering his head to see how far others would lower their heads.  LeBron demands that Durant offer less.  And LeBron keeps offering less himself to see how far Durant will obey the natural order of the universe.

Okay, that’s a pretty silly explanation.  I will note, though, that this story is no more silly than the convoluted explanations I have seen across the past few years for why Allen Iverson had a low-level of shooting efficiency and Eddy Curry was not very good at grabbing rebounds (my explanation…Iverson can’t shoot and Curry can’t rebound).  But if you have an even sillier explanation for any of this, please feel free to post it in the comments J

- DJ

P.S. Forgot to mention one explanation for Durant’s decline… sometimes over small samples of games a player’s performance can deviate from his long-run average.  In other words, random stuff happens.  There might be another explanation.  But the “random stuff happens” is sometimes the best explanation and should be considered before the “convoluted explanations” are tossed out there.