Common sense tells us that if an NFL team scores a lot of points but does not give up a lot of points that team will have a high point differential (referenced by PD throughout the duration of this article). The team will most likely have a successful season. Maintaining a high PD is easier said than done, but it is interesting to look at the statistics.
In 2013, the two teams with the largest, positive PD during the regular season, the Denver Broncos and Seattle Seahawks, battled it out in Super Bowl XLVIII.
With the exception of the Arizona Cardinals (PD of 55) and the Green Bay Packers (PD of -11), the teams that made the playoffs in 2013 also had the highest PDs of all 32 teams.
Denver Broncos = 207
Seattle Seahawks = 186
San Francisco 49ers = 134
Kansas Chiefs = 125
Cincinnati Bengals = 125
Carolina Panthers = 125
New Orleans Saints = 110
New England Patriots = 106
Philadelphia Eagles = 60
Indianapolis Colts = 55
San Diego Chargers = 48
Green Bay Packers = -11
A positive point differential is generally required to make the playoffs–while a PD of 60 all but guarantees entry.
Over the past decade the average PD of Super Bowl champions was 107.2, and between 2000 and 2003 the average PD was 131.75. In 2007 and 2011, the New York Giants broke the mold with PDs of 22 and -6 (Philadelphia Eagles fans would agree that the Giants got very, very lucky and had superb defensive-play). If those two values are eliminated the average jumps to 132.
Surprisingly, the Giants only averaged a PD of 12.6 over the past 14 seasons and have 3 Super Bowl appearances with 2 wins. Contrarily, whether the New England Patriots may or may not be cheaters, football fans should probably respect that their average PD since 2000 is 129.6 (Spygate happened just before the Super Bowl in 2008 and since then the Patriots have averaged a PD of 158.5). The difference in average PD is substantiated by the fact that the Giants made the playoffs 7 times with 3 conference championship-game appearances in that time span, while the Patriots reached the playoffs 11 times with 8 conference championship-game appearances.
The Patriots have gone to the Super Bowl 5 times and won 3 championships since 2000. Like it or not they are pretty much the gold standard of the NFL. If Eagles head coach Chip Kelly wants to be mentioned along with the Belichicks and Lombardis he needs to increase the Eagles PD–and if Philadelphia ever wants to win a Super Bowl the Eagles need to consistently keep their PD above 100 (aka defense…defense…defense).