Seattle Seahawks led the league in points allowed for the fourth straight season (AP Photo/Rick Scuteri)

The NFL playoffs are here, and that means we are going to hear a lot of cliches. Perhaps none more frequently than “defense wins championships.”

Never say never.

You need defense of course — it’s hard to advance in the playoffs if you give up a touchdown on every drive — but its importance tends to be overstated.

Since the NFL is always evolving and adapting, it is best to use the Simple Rating System to compare teams in the same year. This is a team’s average point differential adjusted for strength of schedule. The rating is denominated in points above/below average, where zero is average. This can be further split into  its offensive and defensive components, giving use a good gauge of how much better or worse than average an offense or defense was in they year in question.

For example, the 2012 Baltimore Ravens were not a defensive juggernaut. They allowed 1.67 points (11th in the NFL) on 5.9 plays per drive (26th), resulting in a defense that was only one point per game above average after adjusting for strength of schedule. The 2011 New York Giants allowed 1.92 points per drive (25th) and were 1.5 points per game worse than average on defense that year, placing them 12th in the NFC and 17th overall.

In fact, if you look at the rankings of offensive and defensive adjusted scoring margins a clear trend emerges: you need a top 10 offense more than a top 10 defense if you want to win a Super Bowl in today’s NFL.

Below are the three-year moving averages for each champion’s rankings. A lower number is better, and, as you can see, more teams are offensively gifted — especially recently. Over the past three seasons, the average ranking of a Super Bowl champion’s defense has been seventh best, which still doesn’t get them to the level of the offense, which ranks No. 6 on average.

Since 2002, when the NFL expanded to 32 teams, the Super Bowl champion has seen its adjusted scoring margin on offense rank in the top 10 nine times compared with eight on defense. That one team difference isn’t to say that the case is closed, but at the very least it makes an argument that offense can be as important as defense to winning a championship.

This year there are only two teams who do not have an offense or defense in the top 10: the Washington Redskins and Houston Texans.  And, not surprisingly, those are the two teams with the lowest probability of winning Super Bowl 50. Only the Minnesota Vikings and Denver Broncos see their offense fall out of the top 10, although Denver does have a historically good defense to fall back on.

According to Football Outsiders, the Broncos will finish in the all-time top 10 for Defense-adjusted Value Over Average, which measures a team’s efficiency by comparing success on every play to a league average based on situation and opponent. Only four teams will have been better:

  • 1991 Philadelphia Eagles
  • 2002 Tampa Bay Buccaneers
  • 2012 Chicago Bears
  • 2004 Buffalo Bills

Of that group only the Bucs made the playoffs, but they did win the Super Bowl. Still, I wouldn’t call that a resounding victory for the “defense wins championships” crowd.

There are some very balanced teams in this season’s playoffs — Arizona, Seattle, Pittsburgh, Cincinnati, Kansas City and Green Bay are all ranked in the top 10 on both sides of the football, with the Seahawks the only team with rankings in the top five for each. And while some will point to Seattle leading the NFL in points allowed for the fourth straight year, don’t forget they also rank fourth in points scored this season.