Inside the Numbers

Notre Dame's defense has been the largest source of concern for Fighting Irish fans this year. Let's go inside the numbers a little bit.

Even casual observers of ND football had figured the offense to be the stronger unit this year. That side of the ball returned 10 starters (11 if you want to count Darius Walker) from a group that showed some promise last year even under the prior staff.

The defense, however, returned only three starters from a defensive unit that was statistically the weakest for ND since 1999.

The raw yardage statistics bear out some of those projections. The offense at almost 39 points per game and almost 480 yards per game ranks among the top offenses in the nation by any measure.

The defensive figures of 24.3 points per game allowed and just under 399 yards per game allowed are much more ordinary. The relatively good news is that while ND ranks about 80th in total yardage defense, it ranks 47th (well in the upper half) in scoring defense. If you had to pick one or the other in which to be relatively strong, you'd rationally choose scoring defense because it's points, not yards, that show up on the scoreboard.

One thing that accounts for this relatively favorable disparity is that ND forces other teams to be relatively inefficient. On average, a college team must travel about 14 yards for every point it scores. ND, however, forces teams to travel about 16.4 yards for every point they score, but on offense is quite efficient, scoring 1 point for every 12.3 yards.

There are several factors that account for these relatively favorable ratios. Probably the biggest one is that ND is considerably favorable (+ 9) on the turnover differential. Moreover, ND had forced some very timely turnovers. Against Michigan, Washington and Purdue the Irish defense forced killer turnovers after the opposition had reached the 1 yard line. If you're going to give up yardage as ND has, it's better to force teams to travel a long ways and come up empty.

Improved special teams play has helped as well. It's a lot easier to play good scoring defense if a team is not getting beat on special teams play as ND did last year. This year ND has scored four "non offensive" touchdowns (all by Zbikowski, two on punt returns and two on interception returns) while ND has allowed only one such score (the interception return by MSU).

Additionally, having a good offense helps scoring defense. Seldom has ND this year gone 3 and out on offense. Thus, even when the Irish haven't scored (and the offense has scored a lot, the 41 offensive touchdowns for ND this year has eclipsed in nine games the greatest total of offensive touchdowns – 36 – scored under the prior coaching staff) that unit almost always moves it far enough to change field position.

Finally, though ND has allowed a lot of passing yardage it has held opposing quarterbacks to 51.5 percent completions (down from about 59 percent last year). Generally a couple of incompletions in a row will kill a drive and ND has for the most part done pretty well in that department.

Let's break things down a little further, however. Simply discussing raw statistics is only as meaningful as discussing one's average golf score. If two players each average 80, but Player A plays a very difficult course and Player B plays an easy one, it's a good bet that head-to-head Player A will defeat Player B.

Thus far this year, ND has allowed 24.3 points per game to teams that score 31.3 in their other games. So in that sense, ND has performed remarkably well, holding teams to exactly a touchdown under their scoring average.

The yardage figures reveal some interesting detail. ND has allowed about 399 yards per game to teams that have in their other contests averaged about 421. So ND holds teams about 23 yards under their yardage average.

More interesting, however, is the way in which the Irish have forced teams to throw more than they'd like. In their other games, ND's opponents have thrown for 238 yards and rushed for 183. Interestingly, ND has faced some of the strongest rushing teams in the country this year in Michigan (178), MSU (205), Purdue (176), USC (243) and Navy (278). ND has allowed, however, only about 131 yards per game rushing against this group – over 50 per game under their averages.

On the other hand, ND has allowed about 267 yards of passing per game to teams that usually throw for 238. So ND has allowed almost 30 yards more of passing than they average in their other contests. This isn't all due to porous pass defense, however. Because ND has been ahead for good stretches of every game except the MSU game, and has generally done reasonably well controlling opponents' rushing, the Irish have done a good deal to force other teams to be one-dimensional.

A good example is BYU. BYU ran for 75 yards (81 under the Cougars' season average) but threw for 317 (11 over their season average). If you can force a team into one offensive dimension, the dimension you'd rather confine the opposition to is passing, not rushing.

Certainly, ND is not yet blessed with a great defense. But that unit has had the Irish in position to win every game. As well as the offense has played, miscues on that side of the ball have contributed to both of the losses. Against MSU the defense forced a fumble near midfield with the score tied at 38 and the offense had an untimely three-and-out that led to overtime. Against USC, up 24-21, the offense went on a drive that looked like it might put the game away but it stalled on a poorly executed pass to the fullback.

It's never fair, of course, to point just to one play in a game and surely there were defensive plays that could've been made that would've won those games too. As in all team sports, ND football wins and loses as a team. Fortunately, this year the wins have greatly outnumbered the losses and the defense surely deserves some of the credit for that. Top Stories