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Building A Better Cowboys Defense: Do Sacks Matter?

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Is there a correlation between sack totals and defensive ranking?

Eric Hartline-USA TODAY Sports

My last attempt at humor failed badly. Here's a shot at redemption.

A Higgs Boson particle walks into a church. The Priest starts yelling, "Get out of here! You Higgs particles call yourself the God particle, that's sacrilegious! You're not allowed in this church!"  The Higgs Boson particle replies, "but without Higgs Boson particles, how do you have mass?

Nailed it. On to football.

There has been a lot of talk, partly fueled by Charles Haley's recent HOF induction, that Dallas's defense is one pass rusher away. The idea of more sacks has become a panacea of sorts; if we could just generate a pass-rush our corners will play better, the defense will improve, and Dallas will be a true Super Bowl contender. And to be fair, that's all true. It's self-evident that more sacks are better than less sacks, that pressure makes coverage easier, and that Dallas, already a Super Bowl contender, will only be better with a stronger pass rush. Those truths are self-evident. Aren't they?

To see how sacks impact a team, I've looked at the sack leaders over the past three years, and how they measure in a few key areas, Pass defense DVOA (which measures how successful a team's pass defense is, based on down and defense, compared to a league average team), Pass Defense Rank (the NFL''s standard ranking, based on passing yards allowed), Passer rating (the average Passer rating against the defense), and win percentage (what was the team's actual record). Here's how last years teams looked.

Sack Leaders
2014
Defensive Pass
DVOA Rank
Pass defense
Rank
Passer
Rating
Win
Percentage
Bills 1st 3rd 2nd 0.563
Ravens 15th 23rd 19th 0.625
Eagles 20th 31st 21st 0.625
Giants 21st 18th 16th 0.375
Chiefs 13th 2nd 12th 0.563
Jags 17th 22nd 29th 0.188
Jets 24th 14th 30th 0.25
Lions 8th 13th 9th 0.688
Colts 10th 12th 14th 0.688
Broncos 5th 9th 8th 0.75
Vikings 18th 7th 23rd 0.75
Packers 11th 10th 7th 0.438
AVG 12.8 13.7 15.8 0.542

I listed more than 10 teams here, the last three teams were tied in sack numbers. As you can see the results are mixed. The Bills led the league in sacks, and that dominance extends to the rest of the defensive metrics we're looking at as well; but that defensive dominance didn't extend to winning games as the team only went 9-7. On the other hand, the Eagles were third in sacks, but had horrible defensive ratings elsewhere; they went 10-6. Smack dab in the middle of the top ten in sacks are the Jets and Jaguars; it's nice they could boast a pass rush because they were horrible defensively otherwise, and their records reflect that. On average a top ten sack team fell outside of the top ten in the other defensive metrics I looked at, and had a slightly worse than 9-7 record. That's not great, but maybe 2014 is an anomaly? Let's look at 2013.

Sack Leaders
2013
Defensive Pass
DVOA Rank
Pass defense
Rank
Passer
Rating
Win
Percentage
Panthers 3rd 6th 10th 0.750
Bills 2nd 4th 3rd 0.375
Rams 15th 19th 24th 0.438
Saints 6th 2nd 14th 0.688
Patriots 14th 18th 9th 0.750
Cardinals 5th 14th 8th 0.625
Chiefs 7th 25th 7th 0.688
Packers 28th 24th 25th 0.531
Seahawks 1st 1st 1st 0.813
Bengals 4th 5th 2nd 0.688
AVG 8.5 11.8 10.3 0.635

The numbers are a bit better here, thanks in large part to the historical dominance of the Seahawks defense. But that large variance is still present; the Seahawks were an all-time great defense, but the Packers, who actually had more sacks, were cellar dwellers in most defensive categories. Still, the sack leaders of 2013 were a pretty impressive group, ranking right around the top ten in our defensive metrics and posting a win-loss record just over 10-6.

Sack Leaders
2012
Defensive Pass
DVOA Rank
Pass defense
Rank
Passer
Rating
Win
Percentage
Rams 8th 15th 14th 0.469
Broncos 5th 3rd 9th 0.813
Bengals 7th 7th 12th 0.625
Packers 9th 11th 4th 0.688
Texans 4th 16th 10th 0.75
Vikings 24th 24th 25th 0.625
Dolphins 1st 27th 13th 0.438
Bears 17th 8th 2nd 0.625
Titans 19th 26th 26th 0.375
Panthers 12th 13th 23rd 0.438
AVG 10.6 14.0 13.8 0.585

We see more of the same high variance in 2012. The number two ranked Broncos were a defensive juggernaut, with the winning percentage to match, but the 9th ranked Titans most assuredly were not. On average, 2012 falls between 2014 and 2013, a top ten sack team lands just outside the top ten in other defensive metrics, and has a win-loss record just a tick higher than 9-7.

What's It All Mean?

I think we can draw a few general conclusions from this data. First, and perhaps most importantly, there is no strong correlation between sack totals and a good defense. Sacks are context driven; strong offensive teams force their opponents to pass, giving them more opportunities. Ironically teams with bad pass defenses can also rack up the sacks as teams pass more to take advantage of their weakness.

Secondly, it's difficult to maintain a consistent pass-rush, and defense in general. Only one team, Green Bay, makes the top ten in all three years, and only seven teams (Bills, Chiefs, Broncos, Vikings, Panthers, Rams, Bengals), make it twice. This is an important thing to remember as we look at how and why Dallas is building the team the way it does. Offense tends to be much more stable year to year than defense

So what does this mean for our beloved Cowboys? First, I think it means we shouldn't splurge on a pass-rusher. Never mind the spotty track record of high profile free-agents, the evidence shows that, even if we do hit on a pass-rusher there is no correlation between an increase in sacks and a better defense. Dallas should look to upgrade its talent yes, but the focus shouldn't be on sacks as much as it is on just finding good, well-rounded players.

Second, I think we can expect Dallas's sack total to rise even without a large influx of talent. Three things lead me to think this. One, I think our offense is going to be just as good, if not better in 2015. This means other teams are going to have to pass to keep up; giving us a lot of chances for sacks. Two, I think we'll see the continued improvement from the two most important positions for pass-rushing; the three-technique and weakside end. Basically we had two rookies at those positions; Crawford had never really played the three-technique before, and DeMarcus Lawrence was a literal rookie. Third, I think sheer variance is in our favor. As I said above, sack totals see huge swings from year to year. An explosive offense and maturation at two key positions put Dallas in prime position to see an upward swing in sack numbers.