by Rivers McCown

Last week we looked over the play-action stats on offense, and this week we'll continue over to the other side of the ball. Play-action defense isn't something that's normally thought of as a big determining factor in an NFL game, but playing disciplined football can be the difference between winning and losing.

Last year no team knew that better than the Carolina Panthers. The Panthers finished with the worst defense in the NFL last year by our DVOA numbers, and their 20.5% DVOA on pass plays ranked 29th. However, what if we told you that the Panthers were merely bad when teams didn't fake a handoff against them? Their DVOA allowed on passes without play-action was just 9.1%, which would have been about 21st in the league last season had that been the full story. However, when teams ran play-action against them -- which they did a league-leading 26 percent of the time -- the Panthers defense gave up a league-worst 50.9% DVOA.

As you might imagine, there are a few different ways to cherry pick stats and really bring out the awfulness of the Panthers defense on play-action. Perhaps the best way to demonstrate it though is that John Beck, yes, John Beck, completed four different play-action passes of 20 yards or more on the Carolina back seven. The name that popped up again and again on the receiving end of the punishment was Captain Munnerlyn. Of the 37 play-action passes against the Panthers that went for 15 or more yards, our game charting project had him in coverage for six of them. Hole in Zone led the way with nine, uncovered receivers picked up six, while Chris Gamble was in coverage on four other occasions.

Between 2010 and 2011 there is no correlation between a team's defensive performance against play-action one year and the defensive performance against play-action the next. However, that's because there was just no correlation between pass defense in 2010 and pass defense in 2011 overall. Between 2010 and 2011, the year-to-year correlation of both total pass defense DVOA and play-action pass defense DVOA was -.06. That's a huge historical aberration, however; from 2002-2010, the year-to-year correlation of pass defense DVOA is .33 (which is awful for most science, but fairly reasonable for professional football). For play-action, if we look at 2009-2010, the correlation was .28.

There also isn't much correlation between the rate a team sees play-action against it and how well they play against it, Carolina notwithstanding. The other teams that faced play-action passes more than 22 percent of the time were all over the map in effectiveness. In fact, last year's best team against the play-action pass, Seattle, saw it 22 percent of the time. The common tie between teams that saw relatively little play-action actually appears to be the 3-4 defense. Of the teams in 2010 and 2011 that saw play-action ran against them in 15 percent or fewer of their snaps, eight of the ten were primarily 3-4 or hybrid teams. That includes repeat appearances by the Dolphins, Jets, and Ravens, as well as near-misses (16 percent in 2011) for the Steelers and Packers. The only two of those 10 that ran a 4-3 scheme were the 2010 Giants and Buccaneers. Perhaps the possibility of that extra linebacker in coverage is making a big difference?

Below is the play-action data from 2011 for all teams, in descending order starting with the teams that faced the most play-action. The columns in green represent performance with play-action on actual passes only, with sacks, scrambles, and intentional grounding removed.