The Most "Efficient" Championship Winning Team In NBA History

 

A few months back, I wrote a post on the most "efficient" premiership winning team in AFL history, and suggested that I might do it for other leagues if I feel enthused. Well, this post looks at the National Basketball Association. That rating again:

Championship Efficiency Rating = (Championships Won / Number of Seasons Played) - Average Probability Of Winning Championship

The average probability of winning championship changes considerably across the franchises given the huge expansion in the NBA; the probability of winning is much less if there are 30 teams compared to if there are only 8 (which there was in the '50s).

The results are not that surprising for those who know their NBA history; the Boston Celtics and Los Angeles Lakers are streets ahead. (For brevity's sake I've cut out all the defunct franchises from the list  below, many of which only played a season or two, although of course they were included when calculating the ratings.) What is more interesting is that only six current teams out of 30 have a positive rating, and one of those just barely. If that doesn't illustrate the 'competitive imbalance' problem in the NBA then nothing does.

Boston 0.191
LA Lakers 0.187
Chicago 0.086
San Antonio 0.073
Miami 0.048
Houston 0.001
Dallas -0.006
Philadelphia -0.015
Detroit -0.016
Portland -0.017
Golden State -0.018
Milwaukee -0.020
Oklahoma City -0.021
Washington -0.032
New York -0.033
Charlotte -0.033
Memphis -0.034
Toronto -0.034
Minnesota -0.035
New Orleans -0.035
Orlando -0.035
Denver -0.038
Indiana -0.038
New Jersey -0.038
Utah -0.039
LA Clippers -0.041
Cleveland -0.041
Phoenix -0.042
Atlanta -0.046
Sacramento -0.048

Note too that Atlanta and Sacramento, despite winning one championship each, come out on bottom, since they played a lot of their histories in a relatively small league with a higher (theoretical) probability of winning.