Does defense win championships? A statistical analysis.

We’ve all heard the old adage “defense wins championships.” Usually, the phrase comes from a traditionalist reminiscing on the suffocating defenses of the 80s and 90s or a hopeful football fan rooting for a team with  subpar offense. In Chicago, we recite the phrase as we watch a stellar Chicago Bears defense exhaust themselves trying to compensate for a woefully inept offense. However, it does not seem like anyone ever offers any definitive evidence to support such a claim.

Over the past few decades, the NFL has undergone an offensive facelift. Gone are the days of run-first offenses and staunch defenses dominating the league. In today’s NFL, passing yards come quick and in bunches. As evidence, we can examine the disparity in passing yards between the 1992 NFL season and the 2018 NFL season. 1992 NFL MVP Steve Young, who finished his 1992 campaign second in passing yards (3,645) and fourth in yards per game (216.6 Y/G), would have ranked 28th in Y/G had he played in 2019, nestled right between Alex Smith and Russell Wilson. Meanwhile, Joe Montana’s best full-season yards per game output (270.8 y/g) would have only ranked 13th in 2018. 

But what do the statistics say? Does defense actually win championships in today’s NFL or are we regurgitating an outdated mantra popularized by a bygone generation? We can test this by considering the past 21 Super Bowl champions. 

First, the parameters: we will consider teams that featured either a top-eight offense, top-eight defense, both or neither. Next, we will calculate the average offensive and defensive ranking of the past 21 Super Bowl champions. Offensive and defensive rankings are determined by aggregate points scored and points against.

Teams featuring both:

10 teams featuring a top-eight NFL offense and a top-eight NFL defense have won the Super Bowl since 1997. These teams include:

• 1997 Denver Broncos (1st in offense, 6th in defense)
• 1998 Denver Broncos (1, 8)
• 1999 St. Louis Rams (1, 4)
• 2001 New England Patriots (6, 6)
• 2004  New England Patriots (4, 2)
• 2013 Seattle Seahawks (8,1)
• 2014 New England Patriots (4, 8)
• 2017 Philadelphia Eagles (3, 4)
• 2018 New England Pats (4, 7)

Neither:

As expected, it is much less common for a team featuring neither a top-eight defense nor a top-eight offense to win the Super Bowl. However, since 1997, it’s been accomplished three times by two different franchises:

• 2007 New York Giants (14th in points scored, 17th in points against)
• 2011 New York Giants (9, 25)
• 2012 Baltimore Ravens (10, 12)

Now that the teams that fit into either the both or neither categories have been listed, we can determine whether offensive or defensive proficiency is more instrumental to championship contention.  Since 1997, only two teams featuring only a top-eight offense have won the Super Bowl:

• 2006 Indianapolis Colts (second is points scored, 23rd in points against)
• 2009 New Orleans Saints (1, 20)

Defense-first teams, on the other hand, have enjoyed much more success, winning the Super Bowl a total of seven times:

• 2000 Baltimore Ravens (14th in points scored, first in points allowed)
• 2002 Tampa Bay Buccaneers (18, 1)
• 2003 New England Patriots (12, 1)
• 2005 Pittsburgh Steelers (9, 3)
• 2008 Pittsburgh Steelers (20, 1)
• 2010 Green Bay Packers (10, 2)
• 2015 Denver Broncos (19, 4)
  

Additionally, since 1997, Super Bowl champions finished the regular season with an average ranking of 8.24 in offensive points scored. Defensively, the average Super Bowl champion finished with a ranking of 7.48. 

So Chicago Bears fans should rejoice. Not only are defense-first teams more likely to win the Super Bowl, but the average Super Bowl champion since 1997 has consistently ranked higher defensively than offensively. No matter how we look at it, an elite defense is key to winning championships in the NFL.