Northwestern football advanced stats: Reasons for excitement and concern

As most of the regular readers here know, I'm an advanced stats guy. Pat Fitzgerald and I have often had light-hearted spats about this, to the point where I made the site's motto "stats are for winners."

There is a lot more that goes into a football game than meets the eye, and thanks to a budding group of intrepid statistical analysts — SB Nation's Bill Connelly, Football Outsiders, etc. — we know a lot more about what goes on in football games other than wins and losses.

Right now, the advanced stats aren't as high on Northwestern as the polls are, in part because the polls simply look at your record and who you beat. Advanced stats also aren't as high on the Wildcats as more traditional stats. Despite being 17th in the AP Poll, the Wildcats rank 45th nationally in S&P+ through three weeks. And despite NU leading the nation in scoring defense, the advanced stats aren't quite as impressed (though the No. 7 rank is still very good):

Basically, Northwestern has improved in one area and can't get much worse in the other, and with three wins under the Wildcats' belt, they have some margin for error to put together a nice season.

Thanks to the outstanding work of Bill Connelly, we now have a better idea of which numbers are the most exciting, and which ones should have NU fans concerned. Here's a look at the numbers that will make or break the Wildcats' season:

Why you should be optimistic

Northwestern doesn't let opponents finish drives

Finishing drives is one of Connelly's "five factors," and it amounts to points per trip inside the 40-yard line. Northwestern is holding its opponents to an astounding 1.78 points per trip inside the 40, the best such mark in the nation. The national average is 4.68 points per trip. Even if the offense continues to be awful, the defense just isn't letting opponents score points.

THEY THREW IT TO VITALE

One of my favorite parts of covering games at Northwestern was last season, when an unnamed sports writer would constantly yell at Fitz to throw it to Vitale. This year, the Wildcats are actually doing that! Vitale has been targeted on 21.7 percent of passes, more than anyone else on the team. Maybe that's not a particularly great thing, but personally, I think NU could really benefit from more passes to the tight ends. Now it's time to get Garrett Dickerson (targeted on five percent of passes) up there.

Nobody can pass on the defense

The Big Ten West isn't exactly full of great quarterbacks, and Northwestern's secondary has been so good that the Wildcats will be able to key in on many of the running backs in the Big Ten, knowing that the secondary can succeed in man coverage. NU has played more man this year than ever, due in part to the athletes it has in the secondary, and that seems to be working out. The Wildcats rank seventh in the country overall in pass defense, 17th in opponent success rate and eighth in opponent explosiveness.

The third down defense is really, really good

You already knew this, but the Wildcats' third down defense is the best in the country — both according to opponent conversion rate, and according to S&P+. That's partly due to the depth NU has and the versatility of its players — if it would be beneficial to go with the NASCAR package or nickel, etc., on third down, NU has the tools to do it. If the defense continues to get off the field on third down and send tired opposing defenses out there, it could help the offense.

Why you should be concerned

Northwestern should have lost a game by now

NU has 2.0 second-order wins, meaning that if the Wildcats played these three games over and over again, playing how they've played, they'd generally go 2-1. Northwestern's win expectancy in the Duke game was actually only 34 percent. There has been some luck involved in this 3-0 start, and that's fine, because these games count, but if your response to the Duke and Stanford games is, "man, our offense is that bad and we're still better than those teams," then you're probably overstating it a little bit. If the offense turns it around, this stat won't matter. But barring a miracle, NU is going to have to get lucky to keep beating that caliber of a team with that kind of performance.

Justin Jackson hasn't been that good

This is going to draw the ire of a lot of people who love Jackson, and he certainly has the vision and quickness to be a really good running back. However, he hasn't been Northwestern's best running back this year.

Jackson does a good job falling forward when run blocking breaks down, but when the line does its job — a "highlight opportunity" — Jackson is only getting an additional 2.8 yards past the roughly five yards of run blocking. That is to say, he isn't explosive at all. Meanwhile, Warren Long gets 7.7 yards per highlight opportunity. Some of that is skewed by his long run, but he has been more explosive.

More than anything, Northwestern needs explosive plays. Jackson hasn't given them that, or anything close.

Turnover luck

Northwestern has been pretty unlucky in the past few years, but the Wildcats are getting an extra 4.47 points per game off turnovers than they are expected to. That's a big difference.

The passing game is more hideous than it seems

Not only does Northwestern lack any sort of explosiveness, the Wildcats aren't even being efficient. Only 30 percent of NU's pass plays have been successful — a successful play is 50 percent of necessary yards on first down, 70 percent on second down and 100 percent on third down — which is good for 123rd nationally, and the Wildcats rank 124th in explosiveness.

The pressure will come off Mick McCall if NU has a good season, but really, it shouldn't. The four-star recruits, while young, haven't shown as much as what they're capable of.