2012-2013 NBA Competitive Balance

Now that the NBA finals are upon us, I thought that I would look back at the NBA regular season and calculate competitive balance using the Noll-Scully measure of competitive balance.  As Dave Berri has written previously and as we wrote in The Wages of Wins, the NBA compared to the NFL, MLB and NHL is rather competitively imbalanced.  During David Stern's first 27 years as NBA commissioner, the NBA averaged a Noll-Scully competitive balance of 2.8 for the seasons 1984-85 to 2010-11.  So looking back at the 2012-2013 NBA regular season, I have calculated the Noll-Scully equal to 2.81 (using the sample standard deviation of winning percent) and 2.76 (using the population standard deviation of winning percent).  In either case the NBA is similar in its measure of competitive balance as it has during the last three decades.