The following table reports the regular season efficiency differential (offensive efficiency minus defensive efficiency) of the 37 teams that have won an NBA title since 1974.
Some quick observations from this table:
- these 37 title teams averaged a 6.5 efficiency differential and 59 regular season wins
- 15 team led the league in efficiency differential (offensive efficiency minus defensive efficiency) the year the team won the title
- 26 teams ranked in the top three in efficiency differential
- No team has ranked 5th in efficiency differential and won the NBA title (that doesn’t really mean anything, but I thought I would toss that out there… and you will see in a moment which fans this observation might make angry)
- only 7 teams ranked outside the top five in efficiency differential (including the LA Lakers in 2009-10, whose mark of 4.9 ranked 7th in the league)
With these numbers in mind, let’s look at each team’s efficiency differential at the All-Star break.
Here are some interesting observations (at least interesting to me) from this table.
- The projected wins are not a forecast of where these teams will finish the 2010-11 season. This is simply the number of wins the corresponding efficiency differential typically translates into across an 82 game season. Efficiency differential explains about 95% of team wins and is considered a better measure of a team’s future prospects.
- The top three in efficiency differential this season are the Miami Heat, San Antonio Spurs, and Boston Celtics.
- The Lakers have improved since last year.
- But the Lakers currently rank 5th in efficiency differential.
- The Dallas Mavericks have the 4th best winning percentage in the NBA. But their efficiency differential suggests this team is not a title contender. And I am not sure a healthy Dirk Nowitzki is enough to close the gap.
To illustrate, let’s move from efficiency differential to Wins Produced for the Dallas Mavericks.
The table above indicates that the Mavericks are led this season by Jason Kidd and a healthy Tyson Chandler. Dallas did recently struggle without Nowitzki, but look at the productivity of Brian Cardinal (a player who got more minutes when Nowitzki was out).
The performance of the Mavericks this season is consistent with a team that will win 51 games across an 82 game season. Dallas has already won 40 games (about six more than their efficiency differential suggests). So they will probably win more than 50 games. But teams with a differential below 4.0 don’t typically win NBA titles.
Then again, teams that are this bad do win more often than the team that ranks 5th in efficiency differential. So maybe fans of Dallas should be more optimistic than fans of the Lakers (then again, maybe not).
P.S. Arturo Galletti has done far more than my simple post in exploring which teams are contenders (or pretenders). Following this link to just one of his recent stories on this subject.