How Much Parity is there in the NFL? Or Why have the Detroit Lions been such a Bad Team for so Long?

The NFL Divisional playoff games are being played this weekend.  We are down to four teams out of 16 in each Conference.  This is the 43rd year of NFL playoffs in which there were Divisional playoffs leading to a Conference Championship game.  For 41 straight seasons, the “final four” in each Conference differed by at least one team from the previous year.  This year, for the first time, the four teams representing the AFC (Broncos, Patriots, Ravens and Texans) are the same ones that advanced to the AFC Divisional playoffs last year.   Every NFL franchise has advanced to the Divisional playoffs at least once since 1970.  These facts make it appear that there is tremendous parity in the NFL.  Despite the changes in the top four teams in each conference from one year to the next, there is no doubt that some franchises are much more successful than others.

If all 25 of the NFL teams who played every NFL season from 1970-2012 were equally successful, they each would have appeared in the Divisional playoffs 11.9 times.*  The following tables list the six most successful teams in each conference, as measured by appearances in the Divisional playoffs.  The Steelers are the most successful franchise with 22 appearances, closely followed by the 49ers and Cowboys with 21 appearances.  The least successful NFC franchise is the Detroit Lions, who advanced to the Divisional playoffs only three times.  The least successful franchises in the AFC are the Kansas City Chiefs and Cincinnati Bengals, who each advanced to the Divisional playoffs only six times each.

Team Number of Appearances in AFC Divisional Playoffs % of Seasons that Team Appeared in AFC Divisional Playoffs
Pittsburgh Steelers

22

51.2%

Baltimore Ravens

8

47.1%

Miami Dolphins

17

39.5%

Oakland Raiders

16

37.2%

New England Patriots

15

34.9%

Indianapolis Colts

14

32.6%

Team Number of Appearances in NFC Divisional Playoffs % of Seasons that Team Appeared in NFC Divisional Playoffs
Dallas Cowboys

21

51.2%

San Francisco 49ers

21

47.1%

Seattle Seahawks

5

41.7%

Minnesota Vikings

19

39.5%

Washington Redskins

15

34.9%

St. Louis Rams

14

32.6%

The Cowboys and 49ers have advanced to the final four seven times as often as the Lions.  The Steelers have advanced to the Divisional playoffs about 3.7 times more often than the Bengals or Chiefs.  If all franchises were equally matched (on average), each would have advanced to the Divisional playoffs from 10 to 13 times over 43 years.  The vast difference in the success rates of the Steelers, Cowboys and 49ers on one hand, and the Lions, Chiefs and Bengals on the other hand, is far too large to be explained by random chance, or the difference between good luck and bad luck.

Another way to measure NFL parity is from one season to the next.  The following table indicates how often final four teams in each conference repeated from the previous season and compares this distribution to what would be expected if there was complete parity in the NFL.   

Number of final four NFL teams repeating from last season Number of times this many final four teams repeated from last season Fraction of times this many final four teams repeated from last season Fraction of times this many final four teams would repeat with complete NFL parity

0

5

5.8%

29.0%

1

26

30.2%

44.6%

2

34

39.5%

23.2%

3

20

23.3%

2.8%

4

1

1.2%

0.4%

Typically two teams in each conference repeat in the Divisional playoffs from last year but with complete parity it would be much more likely that only one team would repeat in the Divisional playoffs from the previous year.  Thus, even though all four teams have returned to the Divisional playoffs in consecutive seasons only one out of 84 possible times (42 years each for the AFC and NFC) the NFL is far from complete parity.

In my view, the biggest deviation from parity in the NFL is that some franchises, such as the Detroit Lions, have been much less successful than top franchises over more than four decades.  If teams were equally matched, on average, I would expect the top franchises to have about 30% more Divisional playoff appearances than the franchises with the worst records over 40 decades.  The NFL shares most revenue equally, and gives advantages to the teams with the weakest record in each year (better selections in the player draft and play weaker opponents in the following season).  Thus, as opposed to other professional sports, long-run differences in the average success of NFL franchises is due primarily to talent differences among  owners, coaches and general managers rather than differences in payroll across teams.

*Note: Complete parity in the NFL occurs when all 16 teams in each conference are evenly matched and there is no correlation in a team’s performance from one year to the next.   Although there were 26 teams in the NFL in 1970, the Cleveland Browns did not play for three seasons in the late 1990’s after their team moved to Baltimore and became the Ravens.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: