One Cool Customer’s fine post on passer rating differential breaks down beautifully.

OCC’s post brought to light the fundamental question in regards to improving the defensive passer rating for the Cowboys:

Is it better to draft a defensive lineman to pressure the quarterback or a defensive back to provide better coverage?

OCC also had a post looking for the best playmaking players in the secondary (http://www.bloggingtheboys.com/2012/4/23/2967211/2012-nfl-draft-finding-playmaking-defensive-backs-for-the-cowboys). Last July, I surmised that improving the pass defense would be necessary for the Cowboys to win a Super Bowl (http://www.bloggingtheboys.com/2011/7/17/2280685/its-not-all-about-the-quarterback-and-yet-it-is) based on data similar to that of OCC. Leading up to the 2012 NFL draft, the Cowboys seem poised to draft a defensive lineman (Cox, Brockers, Poe, or Coples) or a defensive back (Kirkpatrick or Barron). Fortunately, the Cowboys made a move to obtain the best secondary player available since Deion Sanders, Morris Claiborne. But would have Dallas been better served to select a defensive lineman that can rush the passer?

Considering that Dallas will be selecting 32nd in the 2013 NFL draft (before any trade), this year may have been the last time the Cowboys selected in the top 20 over the next few decades. So which position would have given Dallas the best opportunity to stake claim to that 32nd draft slot in 2013?

In order to answer this question, however, I must ask several other questions. Please take out your number 2 pencil, put away your mobile phone, and refrain from talking, looking around, or engaging in generally suspicious behavior associated with Eagles fans.

Which NFL team sacked opposing quarterbacks for more lost yardage than any other team in 2011?

Hint: no other NFL team registered more sacks against opposing quarterbacks than the team referenced above.

The 2011 regular season NFL sack leader played a large role in helping the team register 50 sacks versus opposing quarterbacks for 342 yards lost. Those sacks were no small task when considering that over half of the games were against Aaron Rodgers (who's was also ranked number 1 in passer rating), Drew Brees (2), Mathew Stafford (5), Matt Ryan (8) Philip Rivers (11), Jay Cutler (13), and Cam Newton (15).

Conversely, the Minnesota Vikings were 32nd in defensive passer rating, yielding a whopping 107.6 to opposing quarterbacks during the 2011 regular season. Considering that no other team had more sacks against opposing quarterbacks last year, perhaps the key to improving defensive passer rating does not lie along the defensive front.

Top ten teams as ranked using defensive passer rating:

1. Baltimore
2. Houston
3. NY Jets
4. Pittsburgh
5. San Francisco
6. Seattle
7. Kansas City
8. Chicago
9. Cleveland
10. Green Bay

In fact, the top ten teams in regards to defensive passer rating average fewer sacks than the league average (36 sacks per top ten team in defensive passer rating versus the league average of 37.13 per team). The average NFL team defended 544 passing attempts, while the top ten teams in terms of defensive passer rating saw teams attempt 542 passes.

The top 7 teams in terms of passes defensed:

1. Green Bay
2. San Francisco
3. Baltimore
4. Houston
5. Oakland (ranked 11th in defensive passer rating)
6. Seattle
7. Kansas City

A correlation exists between the quality of coverage and defensive passer rating. The top seven teams in passes defensed (see the full list here) are all among the top 11 teams in defensive passer rating and average approximately 115 passes defensed, while the league average was a little over 89.

Those same teams boast an average defensive passer rating of 73.6. The league average defensive passer rating was 82.5. The seven teams with the fewest passes defensed had a defensive passer rating of 92.7.

The bottom seven teams in passes defensed:

26. Philadelphia
27. St. Louis
28. Tampa Bay
29. Dallas
30. Denver
31. Minnesota
32. Indianapolis

Compared to the bottom ten teams in defensive passer rating:

23. St. Louis
24. Washington
25. Dallas
26. Buffalo
27. San Diego
28. Denver
29. Tampa Bay
30. Carolina
31. Indianapolis
32. Minnesota

Furthermore, opposing quarterbacks complete fewer of their pass attempts against the top ten teams in terms of defensive passer rating (56.9% v the league average of 60.1%) for fewer yards per attempt: 6.34 yards/attempt versus 6.75 yards/attempt. Generally a lower yard per attempt leads to a higher pass completion percentage, as shorter passes are easier to complete.

These statistics suggest that teams that boast good defensive passer ratings do so as a by-product of good tight coverage. In addition to the reduced yardage given up, teams with better coverage also yield fewer touchdowns (18.7 TD’s v 23.3 TD’s) and garner more interceptions (19 INT’s to 16 INT’s).

The Dallas Cowboys surrendered 24 touchdown passes and only accumulated 15 interceptions during the 2011 regular season. The Cowboys were 29th in defensive passer rating in 2010 (surrendering 33 touchdowns and collecting 20 interceptions). The Cowboys have not had a season with more interceptions than touchdowns given up in at least ten years. In fact, the number of interceptions in 2010 (20) was the most in at least the last ten seasons.

* Ranked #1 in defensive passing yards in the NFL
" Ranked #1 in sacks in the NFL
^ Denotes playoff season

In 2011, Dallas sacked opposing quarterbacks 42 times (Minnesota led the league with 50), tying the team for 7th in the NFL. Like the Vikings, the Cowboys had a productive pass rusher (DeMarcus Ware) just missing his second 20 sack season. Dallas finished with the 25th ranked defense relative to opponent passer rating.

Division rivals Philadelphia, New York, and Washington finished with 50, 48, and 41 sacks respectively. Those teams finished ranked 19th, 21st, and 24th respectively in defensive passer rating, despite registering well above the league average in sacks.

With the Giants winning the Super Bowl a few months ago, it is easy to assume that a powerful pass rush is the key to victory in the NFL. Improving the pass defense to make it difficult on opposing quarterbacks, however, seems to be closely linked to the quality of the secondary.

Improving the secondary (Jonathan Joseph) helped Wade Phillips’ defense in Houston obtain the second best defensive passer rating in the NFL last season. Combining Morris Claiborne with Brandon Carr should provide a greater boost in Dallas, and sets the cornerstone for a Super Bowl caliber defensive unit.