If you are anything like me, you've been tired of the constant refrains from tv announcers extolling the virtues of the SEC defenses for a while now. College students risk their lives trying to play the "SEC" drinking game while watching an ACC matchup on tv. The breaking point for me was hearing an announcer proclaim that FSU "almost has an SEC-style defense" in the leadup to the game this weekend. If we were only so lucky to be able to run with Mississippi State.
One of the comments I continually hear on ESPN and other coverage-- and the leadup to the most anticipated ACC matchup in years is no exception-- was how the number of defensive linemen SEC teams are able to rotate in throughout a game is particularly influential to the teams' success and something truly unique to the conference. Well, that's a testable hypothesis. Is it true? Do SEC teams really rotate more linemen than their brethren from other conferences? What about the banner defenses of the conference? I decided to take a look at the data. What I found will probably surprise you.
1. The SEC teams do indeed use more DLmen than the ACC. A whopping 1/4 more of a defensive lineman than the average ACC team. The average for SEC teams: 7.25 Dlinemen contributing at least ten tackles in 2011; the ACC average: 7. Not exactly a difference warranting the endless media attention.
2. Also, the SEC doesn't just put more bodies in the game, they get more production from their 2nd and 3rd rotation linemen than the ACC. To the tune of 1% more!! That's it. Average percentage of 2011 tackles coming from the top four linemen on a team in the SEC: 68%. In the ACC: 69%.
So I am pretty comfortable putting this whole SEC is unique in their ability to rotate Dlinemen thing to rest.
It gets more interesting though. What about those top tier defenses? Maybe these announcers really mean Bama and LSU when they say "SEC"-style. This chart has the percentage of DL tackles coming from a team's top four down linemen for ACC (red), SEC (blue), and top ten FEI teams with 2011 data.
Not surprising readers of this website, the 'Noles are right up at the top in sharing their workload with a heavy second/third team rotation. But Bama and LSU are pretty middle of the road as far as getting production out of the second- and third-team Dline goes. The top ten defenses are scattered throughout. There isn't any clustering near the top. Not of SEC teams as a whole. Not of the top tier SEC teams. They just aren't very exceptional in their use of rotating linemen.
And it makes sense. If you are a coach, you are going to rotate out as much as you can without a huge drop-off in production. If you are starting out with 3-star talent, you are probably pretty comfortable swapping out for 3-star talent. There really isn't much reason to expect that swapping out big bodies on the defensive side should be a phenomenon only enjoyed by the upper echelon defenses. Of course, as FSU fans know, when you can do that consistently with top notch talent, you can really enjoy the rewards. It really is the variance up and down the depth chart that is going to dictate how much you swap out. FSU is blessed to have really talented starters... AND an unusually even depth chart. For Texas, Alabama, and USCe, this meant 6 Dlinemen with more than 10 tackles on the year. For FSU and LSU, this meant 9 bodies.
Percent of production coming from the first team Dline along the bottom, 2011 FEI defense rank along the left. There is no correlation between teams rotating out linemen and overall defensive performance. Statistically speaking, how much production you get from the 2nd and 3rd team Dline accounts for 0.6% of the variation in production between defensive units. The complete lack of association there was the most surprising thing out of this exercise for me.
So, in the end, who had the most "SEC"-like defense in 2011? Arkansas. With FSU a close second.
I hope we can all now feel a little more justified when we start throwing things at the tv.
Some postscript notes for the nerds: This is all from 2011 data from cfbstats.com and football outsiders' FEI rankings, garbage time not excluded. Out of curiosity, I looked at these considering only the top 3 linemen, as well, to account for teams who like to run a lot of 3-4 (looking at you Bama), and it didn't change much of anything... all came out very similar. Tackle production isn't the best measure for Dline playing time, but I wasn't going to try and figure out how many snaps every lineman played on a bunch of teams. If you know of those numbers sitting somewhere, let me know. I think tackle production is a pretty good proxy, at least for measuring quality snaps out of people.
Oh, and long, long time reader, first post. Hope the charts show up.