Despite Some Misleading Numbers, the Stanford Secondary is Improved

Editor's Note: SB Nation's Bill Connelly lauded the Cardinal's defense through two weeks in this piece, pointing out the miniscule 2.4 yards per play Stanford allowed against Duke after limiting San Jose State to 4.2 yards per play one week earlier. For anyone still concerned about the Stanford secondary's performance to date, longtime Rule of Tree commenter Darius Tahir (@dariustahir) explains the importance of context when reviewing stats and looks ahead to tomorrow's big test against USC.

Is there some way we can get the allegedly-damning-evidence that the Stanford passing defense has allowed 574 yards through two games thrown out? It’s incredibly misleading. This isn’t to say the Barkley/Woods/Lee trio won’t light up the Stanford secondary, but that’s more due to moving up several weight classes—say, welterweight to heavyweight—than any particular defects the Cardinal have shown versus their opponents so far.

Saying a defense has given up 280 yards passing is useless without knowing whether it took 10 or 280 attempts to get there. In this case, knowing that Stanford opponents have thrown the ball 98 times (for about 5.85 yards per attempt) is what’s known as important context. Or the fact that Stanford’s yards per attempt surrendered is second in the Pac-12, to Oregon. Again, important context.

At any rate, the manner in which Stanford opponents have passed the ball—with a marked emphasis on those short little passes that require quick reactions and sure tackling from the secondary—actually turns out to be decent preparation for USC.

I selected a few games -- Stanford (2011), Oregon (2011) and Syracuse (2012) -- to show the passing mix USC uses to attack opposing defenses, at least in terms of distance down the field it’ll attack with the actual pass (as opposed to yards after catch.) (Note: the Stanford game excludes data from the OT periods. OT periods are magical fantasylands with great field position and exhausted defenses. For example, Stanford did a pretty decent job on defense against USC in standard time—27 points surrendered—but then overtime happened. Also, you’ll notice the number of passes attempted deviate upwards from the official pass data. That’s because I count passes attempted on plays wiped out by penalty and give my best guess on some other plays, e.g. sacks. The idea is to try and ascertain what Kiffin and the Trojans would want to do in an ideal land without referees and sacks and what have you.)

USC gets a lot of hype for being a downfield, aggressive offense, and by first glance at the numbers, you might be inclined to say that that hype is undeserved. I don’t think that’s the best reading of the numbers, however. I’d argue somewhat differently: USC is defended in a way that makes those little dink-and-dunk passes profitable, and that’s due (in part) to the hype. But of course Marqise Lee and Robert Woods are lethal weapons deep, so perhaps this is the best deployment of resources. The key for USC’s offense is that both of these guys are multifunctional: they can go deep; they can also embarrass your defensive backs’ attempts to tackle short.

USC, if anything, might be more inclined to go short this week than usual. With Khaled Holmes going down, and Matt Kalil absent, the USC offensive line may be patchy—and that’s exactly what you don’t want against a relentless Stanford defense. Short throws and Barkley’s quick release might be a perfect antidote.

Which puts things on the defensive backs’ tackling skills. They were excellent tackling against Duke, which accounts for Sean Renfree’s 70% completion rate and his 5.0 yards per attempt. In fact, if we just want to consider the first two games, the defensive backs are ahead of last year’s pace (ever-so-slightly):

TDs have gone up, but only slightly. Completion percentage is substantially up, probably due to opponents’ testing us in short passing situations (which is not, given the secondary’s tackling troubles last year, the most irrational strategy ever conceived), but that is way counterbalanced by the dramatic decrease in yards per attempt and passes picked. (Of course, there are some confounding factors: Stanford had one away and one home game in 2011 versus two at home in 2012; on the other hand, San Jose State is another year deeper into the MacIntyre coaching regime and Sean Renfree should theoretically be at the peak of his powers as a senior…so who knows?)

The secondary appears much better, through two games. Can it make it three? It remains to be seen.