The Injury-Resistant Houston Rockets or How the Rockets Defy Pareto

The story of the Houston Rockets across much of the past ten years has been one of high hopes dashed by injury.  Much of this tragedy has focused on Yao Ming, who entered the league in 2002 as the number one draft pick but has subsequently played fewer than 60 games in five of his nine NBA seasons (including only five games across the past two years).  Although injuries have hit Ming hard, he is not the only Rocket star to spend significant time just watching basketball in Houston.  Tracy McGrady came to Houston in 2004 and across the next five NBA seasons missed more than 100 regular season games.

The injuries to Ming and McGrady might leave fans of the Rockets thinking their team is cursed.  Certainly one wouldn’t think that this team could be described as “injury-resistant”.  But this is exactly the argument I am going to try to make.

The Pareto Principle Again

The story I am going to tell doesn’t begin in Houston, but a bit further to the East. 

Okay, more than a big further.  The big story in the NBA is in Miami.  And when we look at this team, we see that the Super Friends — LeBron James, Dwyane Wade, and Chris Bosh – have combined to produce 27.9 wins so far this year (prior to Thursday night and according to the automated Wins Produced numbers from Andres Alvarez).  This total is 75.6% of the Heat’s 36.5 Wins Produced. 

Although much attention is paid to the Super Friends, a similar story can be seen with respect to the Boston Celtics and LA Lakers.  The Lakers are led by Lamar Odom, Pau Gasol, and Kobe Bryant.  This trio has combined to produce 28.0 wins, or 78.9% of the team’s total.  And the Celtics trio of Rajon Rondo, Kevin Garnett, and Paul Pierce has combined to produce 25.8 wins, or 73.3% of the team’s Wins Produced.

The dominance of a team’s top three players is not unique to these three teams in 2010-11.  From 1977-78 to 2009-10, the top three producers of wins on each team has produced – on average – 76% of their respective team’s total Wins Produced.  This pattern illustrates the Pareto Principle, which states that 80% of outcomes can be linked to 20% of people.  Although it’s not clear (at least to me) how much this simple rule – originally noted by the famed economist Vilfredo Pareto – applies in the general economy; as noted in the past, it does appear that the Pareto Principle works in the NBA.  

Houston History

To further illustrate this story, let’s return to the subject of the Houston Rockets.  The Rockets won two NBA titles in 1994 and 1995.  But in 1996, the Chicago Bulls – led by Michael Jordan, Dennis Rodman, and Scottie Pippen – won 72 regular season games and the NBA title.  This trio combined for 57.5 Wins Produced, or 78.5% of the team’s total. 

As if to specifically counter the dominance of the Chicago Bulls, the Rockets added Charles Barkley in 1996.  Sir Charles joined a team that already had Hakeem Olajuwon and Clyde Drexler.  In 1995-96, this trio missed nearly 40 games.  But had they each played an entire 82 game season, this trio would have posted the following numbers in 1995-96:

  • Charles Barkley: 21.7 Wins Produced
  • Clyde Drexler: 18.2 Wins Produced
  • Hakeem Olajuwon: 16.9 Wins Produced

Altogether, this trio would have produced – if healthy for the entire 1995-96 season – 56.9 wins; a mark quite close to what the Bulls leading trio produced that season. 

So hopes were quite high for the Rockets in 1996-97.  Unfortunately, although Olajuwon only missed four games, Hakeem’s productivity declined (he was 34 years of age).  And Barkley and Drexler missed 49 games. The Rockets still advanced to the Western Conference Finals, but lost in six games to the Utah Jazz (one of the better teams to never win an NBA title).

The idea that a magical trio, though, could lead a team to the promise land persisted in Houston.  When Drexler retired after the 1997-98 season, Scottie Pippen was brought in to complete the trio.  In the lock-out shortened season of 1999 this trio did combine to produce 92.8% of the team’s Wins Produced.  But after a first round loss to the LA Lakers, and the continued aging of the Rockets’ top trio, this team began to take a different direction.

Before we get to that direction, let’s review the history of the Rockets before this past decade.  The following table reports the top trio in Wins Produced for the Rockets from 1977-78 to 1998-99.

The key number is the percentage of wins produced by the top trio.  From 1977-78 to 1998-99, the percentage of wins produced by Houston’s top trio averaged 83% and only fell below 70% once (in 1994-95).  Before moving on, I also want to note that the top trio on each of these teams averaged 34.4 Wins Produced, while Houston’s teams across these 22 seasons averaged 42.4 Wins Produced.  In other words, everyone else on the team only averaged 8.1 Wins Produced.

The Rockets Today

Again, the dominance of a team’s top trio is not unique to the Rockets from 1977-78 to 1998-99.  This is often how teams are structured in the NBA.  But after the 1998-99 season — as the following table illustrates — Houston began to build their team’s differently. 

Across these eleven seasons, the percentage of wins produced by the top three players on the team has never exceeded 66.8%, and the average has been 56.5%.  The top trio has also only produced an average of 25.1 wins per season.  But the players not in the top trio are producing 19.6 wins per season.  Consequently, although the Rockets “stars” can’t match what we saw before 1999-00, the teams in Houston are actually a bit better.

And this story continues this year.  The following table reports the Wins Produced we see from the players on the Rockets after 51 games in 2010-11.

The Rockets are currently led by Kevin Martin, Shane Battier, and Kyle Lowry.  This trio has produced 14.1 wins this season, or 54.8% of the team’s total.  If this trio was what we had typically seen in the NBA – where a team’s top trio produces 76% of a team’s wins – then the Rockets would currently have about 18 Wins Produced.  And that would put them on pace for about 30 wins this year.  Just as we have seen across the past decade, though, the Rockets are much more than their top three players.

When we look past the top trio we see five players – Chuck Hayes, Luis Scola, Chase Budinger, Brad Miller, and Patrick Patterson – who are above average (or very close) and who have played more than 300 minutes.  These five players have already produced 11.3 wins.  And because the Rockets have these five players, the team’s efficiency differential (offensive efficiency minus defensive efficiency) is 0.1.  No, that isn’t very impressive.  But it is consistent with a 0.500 team, which is better than a team that wins only about 30 games. 

Now let’s return to the subject of injuries.  Imagine the Heat lose LeBron and/or Wade (which almost happened on Thursday night).  Or the Lakers lose Kobe and/or Gasol.  Or the Celtics lose Garnett and/or Pierce.  What do we expect to happen?  Because these teams rely so much on their top players – as team’s throughout NBA history have generally done – an injury to one or two top players can dramatically change a team’s fortunes. 

Across the past decade, though, the Rockets have relied less on their top players.  So when these player get hurt – as has often happened – the Rockets haven’t collapsed.  In other words, the Rockets are “injury-resistant”. 

Of course that doesn’t mean that injuries don’t hurt (pun intended).  Houston would be better off this year with a healthy Yao Ming.  But Houston seems to be constructed so that impact of losing a top player is less than what we would see on other teams. 

Let me close by noting that this Daryl Morey has been responsible for building the Rockets since 2007.  And since 2007, the team’s reliance on the top trio has declined. The trend we are observing, though, pre-dates Morey’s arrival.  So this may not be about the current decision-makers in Houston.  But whoever is responsible, how Houston is currently building its team, does seem different from what we have seen in the past.   And the practice of defying Pareto, does appear to yield some benefits.

- DJ

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