Analysis

10/14/20

3 min min read

Do Defenses Really Win Championships in the NFL? (Hint: The Answer Is Bad News for the Seahawks)

We’ve all heard the age-old saying, “Defenses Win Championships,” but how true has this been for NFL teams in the 21st century? As the NFL has developed into a pass-first, offensive heavy league, one might expect to find that Super Bowl champions over the last 10 years have relied more heavily on offensive rather than defensive performance.

The Data

In this study, I focused only on the winners of the past 21 Super Bowls (2000-2019). I started by ranking each of the victor's offenses and defenses in terms of yards/game and points/game. Once I determined these values for each Super Bowl winning team, I averaged their rank from the two defensive categories to find an average defensive rank, and did the same for the offensive side of the ball to get an average offensive rank.

Findings

The 2005 New England Patriots were the only team in the data set that had the same average defensive and offensive rank in a Super Bowl winning year (the cells highlighted in grey below). Of the 20 other seasons, I found the data was split directly in half. In 10 of the seasons, a Super Bowl-winning team’s average defensive rank was better than their average offensive rank, while for the other 10 seasons it was the exact opposite. Although we have seen teams put up record-breaking offensive seasons in the last few years, it seems defensive performance hasn’t become any less important.

However, looking deeper, we can see that many more champions had defenses with an average rank of 5 or better. In 11 of the 21 seasons (52%), the average defensive rank for a team was 5 or better.

The first graph below is coordinated to show results in terms of average defensive rankings.

  • The green points represent teams that had an average defensive rank of 5 or better (2 teams had a rank of 1).
  • The yellow points are representative of teams that had an average defensive rank between 5.1-15.
  • The red points represent teams that had an average defensive rank 15.1 or worse.

This chart supports the idea that having an above-average defense results in a higher chance of championship success.

The second graph shows the data in terms of average offensive rankings.

  • In only 6 of the 21 seasons (28.5%), the average offensive rank for a team was 5 or better.
  • The data shows that many more teams had an average offensive rank in the 5.1-15 range.

What does this mean for teams in 2020?

It’s fair to say that having an exceptional defense can only get a team so far if the offense fails to score points. However, the results show that in most cases, teams are better off having a higher-ranked defense and an average offense than vice versa.

This might be bad news for the 5-0 Seattle Seahawks. The Seahawks rank ninth in yards/game and second in points/game on the offensive side of the ball (average rank 5.5), but they’re 32nd in yards/game allowed and 20th in points/game allowed (average rank 26). A team with similar numbers through five weeks is the Dallas Cowboys, who rank first in yards/game and third in points/game (average 2), but 27th in yards/game allowed and 32nd in points/game allowed (average 29.5). Poor defensive performance has caught up to the Cowboys -- leaving them with a 2-3 record. Will subpar defensive play catch up to the Seahawks as well?

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