Mining the Box Score (Sort of): MSU-Notre Dame

In between microanalyzing and revelling in The Fake, we've actually covered most of the key statistical indicators from Saturday already, so I'm not going to do a full Mining the Box Score post this week.  But I did want to update the disruption percentage numbers (America's fastest growing football statistical phenomenon!  I.E., Two of us think it's cool now.)

A quick refresher for newer readers:

Boiled down to its basics, playing offense successfully in the sport of football is pretty simple:

• Gain 10 yards in 3 tries.
• Repeat until you reach the the end zone.

. . . At the hypothetical extreme, a team that could gain exactly 3.5 yards on every play could achieve that goal.  Alternately, two rushing plays of 5 yards each or a single pass completion in three attempts for 10 yards does the trick.

The goal of any football defense, then, has to be to disrupt the opposing offense's rhythm, with the goal of creating a situation where picking up 3-5 yards per play isn't enough to keep a drive going.

In an attempt to quantify the success (or lack thereof) of the Michigan State defense in disrupting opposing offenses, we here at TOC have developed a new-fangled metric we call "disruption percentage."  The percentage is calculated by summing the five defensive statistics below (presented in ascending order of disruptiveness) and dividing the total by the number of offensive plays run by the opposition:

• Quarterback hurries: Increasing the odds the offense will throw an incomplete pass and lose an opportunity to gain yardage toward a first down
  
• Pass break-ups: Ending an attempted pass play and reducing the number of downs the opposition has to pick up a first down
• Tackles for loss: Increasing the yardage the offense has to gain to achieve a first down by sacking the quarterback or stopping a running play for a loss
• Forced fumbles: Creating the opportunity to recover a fumble and end the opponent's offensive possession
  
• Interceptions: Definitively ending the opponent's offensive possession

For context, MSU's defensive disruption percentage numbers from last year are after the jump:

(Technical note: Last year, I took a liberal approach to forced fumbles, counting all fumbles by the opposition.  This year, I'm counting only true forced fumbles.)

While I ran the numbers for other Big Ten teams last year, I'm now thinking that cross-team comparisons may not be fully valid as there appears to be some inconsistency in how scorers award quarterback hurries.  MSU posted 30 of them last season, while Penn State recorded just 9.  That doesn't seem like it can be right.  (The same phenomenon is present--and even more extreme--in other conferences.)  So I'm working off the assumption that MSU scores its own defensive stats (since there doesn't appear to be any home/away bias), which allows us to at least compare MSU's disruption numbers across the season (and maybe between seasons).

Anyway, here's where things stand for the MSU defense through three games this season:

The overall disruption percentage against Notre Dame is higher than I would have thought, but the numbers mask an underlying trend.  Of MSU's 16 total disruptive play, only 6 were made by defensive linemen--and none of those 6 plays were tackles for loss.  (As noted by LVS today, though, one of them was pretty huge--the tipped pass by Jerel Worthy on Notre Dame's first play of overtime.)  Generally, it was left to the MSU linebackers and secondary to make plays.  Four of MSU's disruptive plays belonged to Chris L. Rucker and three belonged to Greg Jones.

Given the lack of pressure up front, the rest of the defense actually did a decent job holding Dayne Crist to 6.7 yards/attempt.  The trick going forward is to combine the pressure up front from last season with the generally more competent tackling and better big-play prevention in the secondary this season.

I'm also going to track the disruption numbers against the MSU offense this season in order to get a sense of how cleanly MSU was able to run its execute its offense in each game.  Note that the QBH scoring issue may be a problem here, though.  Here are the numbers:

Again, the number for the Notre Dame game is somewhat misleading.  Several of those TFLs/QBHs came on passing plays in which Kirk Cousins held on to the ball for an extra moment or two in hopes of making a big play.  More concerning perhaps are the four non-sack TFLs posted by Notre Dame.  In the two warm-up games, MSU had avoided negative running plays almost entirely.  The running game was certainly still very effective overall, but avoiding losses will be a priority going into the Big Ten season.  (Crazy running game stat: Edwin Baker only needs 79 yards this Saturday to pass Larry Caper's team-leading 468 rushing yards of last season.)