by Andrew Healy
For this year's edition of the cornerback charting stats, we are conducting the festivities Academy Awards-style. We will be handing out Best Cornerback awards both in a leading role (No. 1 corner) and a supporting role (everyone else). As with the Oscars, these distinctions are imperfect. The leading corner is not clearly defined on every team. But with all the work we do to adjust for the quality of opposing receivers, it ends up making more sense to try to separate the Darrelle Revises and Richard Shermans of the NFL from the Orlando Scandricks and Corey Grahams (much more on him to come).
As in the past, the cornerback charting stats come from the Football Outsiders Game Charting Project. We track two main stats in particular, adjusting each for the quality of opposing receivers:
- Yards Per Pass, which is just the average yards the corner allowed when targeted.
- Success Rate, which is the share of targets on which the corner prevented a successful gain (45 percent of needed yards on first down, 60 percent on second down, and 100 percent on third down).
We are identifying the plays in which the cornerback is listed as the primary defender in pass coverage, ignoring a few types of plays unlikely to reflect on the cornerback. Specifically, we ignore screens, balls tipped at the line or thrown away, Hail Marys, and plays where the quarterback was hit while throwing. We include pass interference, but ignore other defensive penalties that often occur away from the pass.
We also report the number of targets that each cornerback faced, as well as a metric we call "estimated target percentage." This stat uses snap counts to estimate what percentage of possible targets were thrown at this player when he was on the field. The "possible targets" part of that metric leaves out the passes noted in the previous paragraph, as well as those passes listed with "Uncovered" or "Blown Coverage," though the total of possible targets does include "Hole in Zone" passes.
The usual caveats about game charting data apply here, as described in last year's article. As always, we need to point out that this is imperfect data charted by a group of volunteers plus a handful of FO staffers. Cornerback stats have been very volatile, bouncing up and down year-by-year for a lot of players, and the best cornerbacks will sometimes rank lower than expected because quarterbacks only throw in their direction when they make a mistake. In addition, with so many players ranked, readers need to make sure to understand that there isn't much difference between ranking 35th and 40th in a metric. For that matter, there isn't much difference between ranking 35th and 50th. As we always say, these stats should not be seen as absolute statements on player value. They're just part of the story.
The stats below are adjusted for the quality of the opponent receivers. These stats compare No. 1 receivers to other No. 1 receivers, No. 2s to other No. 2s, and so on. We are considering changing these adjustments in the future, perhaps by comparing receivers being covered to all receivers rather than just other receivers of the same "receiver position," but we couldn't do that for 2014 due to time constraints. Nevertheless, the current adjustments provide interesting insights, particularly when we break down the data by separating No. 1 corners from other corners.
As described earlier, the No. 1 corner is more obvious in some cases than in others. Some teams use their starting corners interchangeably, while other teams saw playing time scrambled by injuries. For this article, we're defining a No. 1 corner as the one on each team who faces the most opposing targets against opponents' No. 1 receivers. This definition usually gives the most logical No. 1 corner, but not always. Even when a team has a clear top corner, he sometimes does not always cover the top receiver (e.g., Kyle Arrington rather than Darrelle Revis guarded T.Y. Hilton for most of the AFC Championship Game, with help from Devin McCourty on almost every play). Still, over the course of the season, the list of top corners mostly accords with common sense. We made two changes (naming Vontae Davis as the Colts' top corner over Greg Toler, and Chris Harris for the Broncos over Aqib Talib), but left the rest defined according to targets. This definition makes Lardarius Webb the Ravens' top corner, not Jimmy Smith, whose season was cut short by a Week 8 injury.
Note that to qualify in either category a corner had to either face 50 targets or start eight games.
Best Cornerbacks in a Leading Role
The chart below has the ten top contenders for the best No. 1 corner in the NFL in 2014. We also included two players who would have made the top ten if we had restricted the sample to players who made at least 14 starts. Ranks represent placement among the 32 cornerbacks we considered as No. 1 corners.
|Top Leading Role Cornerbacks by Adjusted Success Rate 2014|