Analytics have a way of upsetting your sensibilities and upending some preconceived notions. Growing up, we’ve been conditioned to believe that pass rush is critical. And for good reason—pressure reduces passer rating substantially (by about 30 points) and nearly halves a team’s yards per play average. And we can see from the broadcast angle when pressure affects a quarterback. Because passing is so important, good pass-rushers have been the highest-paid members of most NFL’s defenses.
However, we found that not only does pass coverage (as measured by PFF grades) explain team success better than pass-rushing, but predicts it better as well. This helps explain why the winningest team in the league (New England) has used its only two big-name defensive free-agent signings on cornerbacks over the past decade (Stephon Gilmore and Darrelle Revis), and why defensive end Trey Flowers is currently a Detroit Lion. One need only to go back to last year’s playoffs to see how the quick passing game of today’s NFL mitigates even the strongest pass rush, with the Patriots racking up 78 points en route to the Super Bowl despite facing the vaunted pass rushers on the Chargers and Chiefs.
The caveat to this finding? As a trait, coverage tends to be less stable year to year. The upshot? Invest a lot into coverage, so that some subset of five or six of these players give you an elite group.
If you’re going to invest in a pass rusher, prioritize his pressure rate, not his sack rate
Sacks are important and worth about two points for a defense. They usually end drives and often force turnovers. They are the ultimate goal of all pass rushers and rightly the most valuable non-turnover play for a defender.
But if you want to know how good a pass rusher is, and how good he’ll likely be the following season, look at his pressure rate. We at PFF define a pressure as a sack, a hit or a hurry on a quarterback, with the best pass rushers able to generate a pressure on 15 to 20 percent of their pass-rush snaps. For a pass rusher with 500 pass rushes during a season, you’re talking about 75 or so plays, versus just 10 sacks.
Generally speaking, “finishing” pressure with a sack isn’t really a trait a pass rusher possesses per se. If you want to predict a player or team’s sack total one year, use his or its pressure rates from the previous season. A 20 percent decline in a player’s sack total from 10 to eight, for example, is mostly noise. But a 20 percent dip in a player’s pressure rate from 50 to 40 is less so. Process over results.