Clemson football: What advanced stats say about the Tigers’ defense
We’re all aware of how potent the Clemson defense is by now.
Just going off of more conventional metrics, the unit ranks among the nation’s leaders in a handful of categories. Clemson is eighth in total defense, 13th in rushing defense, 15th in passing yards allowed per game, 14th in defensive third down conversion percentage, and fifth in sacks.
You can glance across those stats and be certain that if an offense is preparing to line up against the Clemson defense, they’re going to be in for a hard day at work.
But when you dig a little deeper, and you take a peek at a handful of more specific metrics, you start to grasp how dominant this unit has been.
It’s already in a tier above the glut of the other defenses in the country, and that’s even when you take into account what it’s done against a couple of high-powered offenses in Auburn — which it shut down — and Louisville, which had Lamar Jackson struggling to figure out what to do for most of the night.
So we’re going to take a look at what making this Clemson defense tick. These stats come from Clemson’s advanced statistical profile, and this is the first of two parts. The second will run next Wednesday, when I’ll take a look at the stats behind Clemson’s offense.
Defensive success rate – 29.2 percent (National average: 40.4)
In college football, success is picking up 50 percent of necessary yardage on first down, 70 percent on second down and 100 percent on third and fourth downs.
It’s not a surprise, then, that Clemson is third in the country here. Teams convert 27.8 percent of third downs against the defense, and they suffer from being forced into a lot of passing downs because it’s tough to get any traction against the Clemson defensive front on standard downs.
When you factor in IsoPPP — which stands for Isolated Points Per Play, a measure of a team’s explosiveness — it becomes easy to see how this fits together. Clemson’s IsoPPP on defense is 0.89, second-best in the country and well below the average of 1.17.
0️⃣ Turnovers on Offense
3️⃣ Forced Turnovers on Defense
1️⃣ W pic.twitter.com/5y4X9AGxWj
— Clemson Football (@ClemsonFB) October 1, 2017
They limit explosive plays and get to the quarterback early. Clemson ranks first in the country in sack rate — the percentage of plays they sack the quarterback — on standard downs, with 12.8 percent, more than twice as much as the average of 5.0.
Teams can’t break big plays against Clemson — the Tigers are tied for the sixth-fewest plays of 20-plus yards in the country — and because they’re getting sacked so much on early downs, they’re often facing an uphill battle, which forces them into longer passing downs.
Passing downs are categorized as situations where an offense is facing second-and- 8 (or more), third-and-5 (or more) and fourth-and-5 (or more). And when Brent Venables’ unit knows a pass is coming, they’re able to corral it, break it up or shut it down. Teams have a success rate of 19.8 percent against Clemson on passing downs, nearly 11 percentage points lower than the average of 30.7 percent.
So, what’s all that mean?
Clemson’s defense is good. Really good, but that wasn’t a secret.
The Tigers limit early down success, and then make sure teams can’t convert on third down.
They rank among the top-3 units in the country when it comes to limiting opponents’ efficiency and explosiveness, and they do well enough in the field position battle and stalling an offense’s ability to finish drives that by the time one finally does manage to figure out Clemson’s defense and tack on a drive or two that ends in points, it’s usually too late.
💪 DEFENSE in the first half.
— Clemson Football (@ClemsonFB) October 7, 2017
By that point, Kelly Bryant and the Clemson offense have done what they need to do to get the Tigers on the board and build a lead. But we’ll talk about that next week.