So here is the Noll-Scully measure of competitive balance for the 2012 NFL regular season. Using the standard deviation of a population yields a Noll-Scully = 1.524 and using the standard deviation of a sample yields a Noll-Scully of 1.549. So is this good or bad? That depends on how competitive the NFL has been in prior years. So I looked at the regular season standings from 1981 to 2011 and as you can see below the 2012 NFL regular season is very similar in terms of competitive balance to prior seasons. For those interested, here is my step-by-step guide to calculating the Noll-Scully measure of competitive balance.
Here is the Noll-Scully competitive balance measures using both the population and sample standard deviations from the NFL's 1981 regular season to the 2012 regular season. As you can see in the table below that the 2012 regular season is not much different than the average during this time period. Average NS (population) from 1981 to 2012 = 1.505 and Average NS (sample) from 1981 to 2012 = 1.531.
| Season | NS Population | NS Sample | ||
| 1981 | 1.364 | 1.389 | ||
| 1982 | 1.677 | 1.708 | ||
| 1983 | 1.370 | 1.395 | ||
| 1984 | 1.651 | 1.681 | ||
| 1985 | 1.540 | 1.569 | ||
| 1986 | 1.639 | 1.669 | ||
| 1987 | 1.372 | 1.397 | ||
| 1988 | 1.320 | 1.344 | ||
| 1989 | 1.415 | 1.441 | ||
| 1990 | 1.591 | 1.620 | ||
| 1991 | 1.710 | 1.742 | ||
| 1992 | 1.625 | 1.655 | ||
| 1993 | 1.260 | 1.283 | ||
| 1994 | 1.375 | 1.400 | ||
| 1995 | 1.204 | 1.224 | ||
| 1996 | 1.448 | 1.473 | ||
| 1997 | 1.429 | 1.453 | ||
| 1998 | 1.682 | 1.711 | ||
| 1999 | 1.470 | 1.494 | ||
| 2000 | 1.549 | 1.575 | ||
| 2001 | 1.600 | 1.627 | ||
| 2002 | 1.300 | 1.320 | ||
| 2003 | 1.509 | 1.533 | ||
| 2004 | 1.515 | 1.539 | ||
| 2005 | 1.668 | 1.694 | ||
| 2006 | 1.425 | 1.447 | ||
| 2007 | 1.634 | 1.660 | ||
| 2008 | 1.631 | 1.657 | ||
| 2009 | 1.585 | 1.611 | ||
| 2010 | 1.474 | 1.497 | ||
| 2011 | 1.610 | 1.636 | ||
| 2012 | 1.524 | 1.549 |