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How Good is the USC Defense?

We use advanced analytics to take a look at just how good Clancy Pendergast's USC defense is.

When Clancy Pendergast was re-hired by Clay Helton as USC’s defensive coordinator, much of the USC fan base on the Peristyle was excited and with good reason, his defense in 2013 was the 4th best according to S&P+. While Pendergast still has some work to do, USC’s defense is currently ranked 21st overall in the S&P+, which isn't top-5, but still pretty good. 

To those thinking about the Alabama result and wondering how that’s possible, the “+” in S&P+ accounts for the quality of the opponent. In that game, USC’s defense gave a 36% performance, which is not nearly as bad as it sounds, considering so much of it was garbage time. According to Bill Connelly, garbage time can be defined as +25 in the 2nd quarter, +22 in the 3rd quarter and +17 points in the 4th quarter. Looking at USC’s advanced statistical profile the Stanford game at six percent (!!!) is the worst defensive performance of the season and given how bad Stanford has looked lately, that seems pretty accurate. Let’s take a look at what this defense is doing well right now and what it can hope to improve as the season goes on.


USC is really good at forcing defenses into tough situations by limiting their success rate, where USC ranks 31st in the country. Success rate measures the offenses’ efficiency, specifically their ability to generate consecutive plays and gain first downs. Within that 21st overall S&P+ ranking, USC has the 15th best rush defense in the country and 31st best pass defense. Again, where they’re successful in both facets is limiting the efficiency of the opponent in both measures. They’re also good on both overall Standard and Passing Downs. In Standard Downs, USC’s defense is great at limiting the offenses efficiency and in Passing Downs they excel at limiting opponents’ explosiveness. Explosiveness looks specifically at the successful plays an offense generates or defense limits and how successful the offense or defense are. Standard downs are 1st-10, 2nd-7 or less, 3rd-4 or less, 4th-4 or less. Passing Downs are 2nd-8 or more, 3rd-5 or more or 4th-5 or more.


USC has trouble limiting explosiveness in both the running game and passing game, ranking 94th and 53rd respectively. These less than ideal rankings prove that opposing offenses tend to break loose for a big play or two during a game. USC’s defense also struggles to get to the QB and it shows as its adjusted sack rate is 98th in the country. It’s also important to look at what Connelly calls “Havoc plays” when evaluating a defensive performance per unit (DBs, LBs, DL). A havoc play is any tackle for loss, pass defensed, or force fumble. The DBs are the position group that is good here, ranking 14th in the country, LBs and DL though are 76th and 88th in the country respectively in terms of the rate at which they’re generating havoc plays. This ties together with the sack rate as those two position groups traditionally are responsible for generating pressure on the QB. While the DB number is typically passes defensed and interceptions, if you look at the individual stats you’ll notice tackles for loss from that group as well.  Lastly, the defensive performance as a whole has a tendency to struggle in the 2nd half as it ranks 100th and 64th in the third and fourth quarters. This was a bigger problem in the beginning of the season which could probably be attributed to the struggles of the offense but it is still present in the behavior of the team.

Overall this is a good defense that has some noticeable weaknesses to keep an eye on as the regular season continues. Most immediately with Cal on Thursday night, as Cal brings in the 6th best offense in the country per S&P+. 

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Saman Djabbari graduated from USC in 2008 and is a weekly contributor to and co-host of the Traveler Hates Thursdays' podcast. You can follow him on Twitter at @samandjabbari. Top Stories