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The Value of Things: Passing Defense

How correlated is passing yards allowed with winning?

NFL: MAR 05 Scouting Combine Photo by Robin Alam/Icon Sportswire via Getty Images

I used to do these kinds of series in baseball all the time. It’s always a bittersweet moment when you get to the end of one. Passing defense effectively closes the book on looking at each facet of the game and it’s correlation to winning. We’ve already seen how strong the correlation between running defense was (particularly when compared with overall defense) so, these results will likely be anti-climatic.

I always try to use these studies as a learning experience. I try to clear my head as much as I can from what I would likely suspect and allow myself to be surprised at the results. Considering that the NFL is a passing league, you’d expect pass defense to be pretty damn important.

I’d add that all evidence suggests that the Texans would agree with that. Two of their top three picks (including their top pick) are secondary players. They signed two corners that were primary starters on their team, and they signed one of the highest PFF graded safeties in the NFL last season. Add to that the fact that Tavierre Thomas and Desmond King graded well when they played the slot and you have the makings of a vastly improved secondary. They jettisoned the worst safety in the business for a conditional 7th rounder and they still have Eric Murray, but Rome wasn’t built in a day.

Add to that all of the edge rushers they added in free agency and you have the makings of an improved pass rush and an improved back end. The question remains though as to whether that is the quickest path to having a good defense overall. The numbers from last time would indicate that the run defense is the key, but maybe we are missing something in the translation.

Number One Pass Defenses

We should start with an admission of sorts. There are all kinds of ways to grade pass defense. You can look at passing yards, completion percentage allowed, net yards per attempt, passing rating against, or DVOA just to name a few. We have settled on passing yards allowed. It’s simplistic and it has its issues like any of those other stats. The main issue is the fact that when teams are behind, they throw the ball. So, good teams will give up more passing yards than bad teams if everything else is equal. Given that caveat, let’s see what we have.

Number One Pass Defense: 6 Super Bowls, 2 conference losers, 3 divisional losers, 4 wild card losers

So, we are talking 15 out of 22 of the top passing defenses making it to the playoffs. Four of the six Super Bowl participants were Super Bowl champions. So, it would appear that having a top rated pass defense is better for you than not. We saw 14 such top rated run defenses, so one could claim that the correlation is stronger for pass defenses. Of course, we have multiple ways to calculate that.

Final Four Teams

We have been doing this for every facet. Essentially, we are looking for two things. First, how correlated is pass defense with winning at all three levels? We can then compare that with other phases of the game (run defense in particular) to see which ones have the strongest correlation. However, the most telling stat is not the ranking itself but whether it gets stronger as teams get more successful. The composite score for Super Bowl champions should be lower than for the runner up and then also lower than conference losers. If it isn’t then something is up.

Super Bowl Champions— 4 top overall, 6 top five, 8 top ten, 12 top half (Composite: 13.3)

Super Bowl Losers— 2 top overall, 3 top five, 5 top ten, 14 top half (Composite 15.8)

Conference Game Losers— 2 top overall, 10 to five, 17 top ten, 28 top half (Composite: 14.0)

We would note that the composite ranks are considerably weaker than the rushing ranks. Again, that can be explained through the normal course of surrendering more yards in the air when you are ahead. The winner had a better pass defense exactly half the time in the Super Bowl. That’s not particularly helpful for those that want to bet on the outcome of the Super Bowl. I’d probably look at another stat first.

Localize It

So, you could argue that Nick Caserio was more invested in fixing the pass defense than any other phase we have looked at. We could possibly justify that in any number of ways. First, we could argue that this was simply where the best value was. Sometimes you just have positions that are more well stocked with prospects than others. We could also look at any number of statistics that measure passing defense and see stronger correlations. Anything is possible. Either way, the Texans should be an interesting test case. Their secondary and pass rush isn’t elite, but it should be much improved. Will it make the Texans that much better? We shall see.