NFL By the Numbers - Sack Differential

NFL BY THE NUMBERS

Sack Differential

Last week I commented on the Toxic differential - a statistic that aggregated a team's turnover differential and its big play differential.

I questioned the predictive value of the toxic differential because a positive toxic differential didn't appear to correlate that closely to positive results on the field. Plays happen in the context of a game and a game's momentum.  A twenty yard big play from the 10 to the 30 is not as meaningful as a 20 yard big play from midfield to your opponent's 30 yard line.  An interception in a lopsided game doesn't really impact end results.

I still think one of the truest predictors of success is a team's ability to rush the quarterback.  I posted earlier in the year that the last ten Super Bowl winners sacked the opposing quarterback an average 23% more than the league average for sacks.  A sack is disruptive.  A well-timed sack can negate the momentum generated by a big play or a turnover.  Conversely, avoiding sacks sustains drives and allows a team to reap the rewards of big plays and turnovers created by the defense.  You can see where this is headed.  Let's look at sack differential as a yardstick of gridiron success.

Through twelve games (thirteen for the Broncos and the Raiders) the top five teams in the league in sack differential (sacks of opposing QBs less sacks of your QB) are:

Houston       +21

Denver         +20

NY Giants   +15

Bengals        +12

Bills              +10

The Bottom five teams are:

Jags              -24

Eagles           -15

Cardinals     -15

Chargers      -13

Jets               -11

Other than the Bills cracking the top five, these numbers correlate pretty well with on field performance.  

Notably - Every Super Bowl winner for the past ten years has had a positive sack differential.  The ten winners averaged a +12.4 sack differential.  History does not currently bode well for the following playoff contenders with negative sack differentials:  - Colt -5, Packers -5, Niners -4, Bears -3 and Ravens -2.  The 2008 Steelers and the 2002 Bucs did win with just +2 differentials, so there is time for these teams to get on the right side of history.