The Irish have emphasized forcing turnovers this year. Such a party line is an inevitable mantra following a season when the defense created only 14 takeaways. It became even more a pertinent point when three turnovers were the primary difference in Notre Dame’s 38-18 victory at Michigan State on Saturday.
“We’ve got smart players, we need to play smart,” Irish coach Brian Kelly said Tuesday. “Part of it is not giving up big plays and taking the football away. We can do that.”
Indeed, Notre Dame can. And thus far this season, it has. Nine turnovers in four games is nothing to scoff at. But is it simply a convenient data point easily explaining the defense’s improvement, especially with Shaun Crawford’s savvy play against the Spartans serving as a tangible example?
No. It is more than that.
Earlier in the same answer as the above quote, Kelly used a phrase few would have expected to apply to the Irish defense this season. He used it in something of a conditional context, but it was there all the same.
“This is not by coincidence,” Kelly said. “This is about crafting the tenets of playing the kind of defense necessary to be a championship football team.”
The last time Notre Dame had a championship-level football team, the defense provided the backbone. 2012’s unit led the nation in scoring defense in the regular season. It was, quite frankly, the reason the Irish made it to the national championship game.
To date, Notre Dame’s 2017 defense is performing comparably with that modern standard of 2012, even if the scoring statistics are not as headline-worthy.
Before closing this window and claiming this space has lost all its marbles, allow for an explanation.
There are four ways for an offense to get the ball back:
1) A kickoff from a score, a sure sign the defense failed.
2) A turnover on downs, something rather situationally-driven as much as anything else.
3) A punt, a sign the defense succeeded.
4) A turnover, a sign the defense succeeded and provided improved field position in doing so.
Aside from that second category because, again, it is determined by an array of factors including score, time, field position, etc., not all necessarily reflecting the defense’s performance, then those categories can break into three defensive results:
1) Scoring opportunities, including missed field goals. Why include those? No defensive coordinator relishes seeing the opposing placekicker on the field. It is simply preferable to seeing a receiver with the ball in the end zone.
2) Punts.
3) Turnovers.
In 2012, Notre Dame’s defense forced a turnover on 16.2 percent of the opposing possessions while allowing a scoring opportunity on 28.2 percent of them.
This year, the Irish have forced nine turnovers on 54 opposing possessions, a turnover rate of 16.7 percent. Only 29.6 percent of opposing possessions have resulted in scoring opportunities.
That turnover rate is the highest of Kelly’s tenure at Notre Dame. The scoring opportunity percentage is bested by only 2012, with the next-closest coming in Kelly’s 2010 debut season in South Bend at 31.3 percent.
(The eight-plus point difference between 2012’s regular season points allowed per game [10.3 in the regular season] and 2017’s thus far [18.5] is easily explained by looking at possessions. Entering this season, Irish offensive coordinator Chip Long was expected to increase the tempo. That uptick has resulted in a 23.6 percent increase in total possessions compared to 2012’s rate and a 13.3 percent increase from just a season ago.)
On a more recent basis, the rate at which Notre Dame is forcing turnovers jumps off the page when compared to the last two seasons. In 2016, only 9.6 percent of opposing possessions resulted in turnovers. Despite the 2016 storyline of the Irish struggling to take the ball by force, that number actually edged up to 9.8 percent. Clearly, this year’s defensive improvements go beyond a few lucky breaks to be within shouting distance of twice those figures.
What does any of this mean? It is intended as a gauge for the defensive performance thus far this year and a reflection on its possible sustainability.
Looking past Notre Dame, how do this year’s rates compare on a national level? Those teams are listed below, but to summarize: The turnover rate lags behind the most-aggressive defenses, but it is consistent with the best scoring defenses. Those latter teams, however, still do a bit better when it comes to limiting scoring opportunities, meaning the Irish have room for improvement, obviously.
On that much at least, Kelly would agree.
“We’re certainly not a finished product by any means,” he said. “We’re going to continue to work on that.”
2016’s leaders in turnovers forced:
Houston — 35 turnovers forced — 18.3 percent of opposing possessions resulted in turnovers — 28.3 percent resulted in scoring opportunities.
Utah — 34 turnovers — 28.8 percent turnover rate — 48.7 percent scoring opportunities rate.
Arkansas State — 34 turnovers — 17.6 percent turnover rate — 29.5 percent scoring opportunities rate.
San Diego State — 34 turnovers — 19.0 percent turnover rate — 25.7 percent scoring opportunities rate.
2016’s leaders in scoring defense:
Wisconsin — 13.7 points allowed per game — 18.2 percent turnover rate — 28.5 percent scoring opportunities rate.
Ohio State — 15.1 points — 16.3 percent turnover rate — 24.7 percent scoring opportunities rate.
Alabama — 15.1 points — 14.6 percent turnover rate — 21.2 percent scoring opportunities rate.
Boston College — 15.3 points — 16.3 percent turnover rate — 32.5 percent scoring opportunities rate.
Notre Dame during Kelly’s tenure:
2010 — 15.1 percent turnover rate — 31.3 percent scoring opportunities rate.
2011 — 9.3 percent turnovers — 31.3 percent scoring opportunities.
2012 — 16.2 percent turnovers — 28.2 percent scoring opportunities.
2013 — 11.5 percent turnovers — 39.8 percent scoring opportunities.
2014 — 14.4 percent turnovers — 38.1 percent scoring opportunities.
2015 — 9.6 percent turnovers — 35.6 percent scoring opportunities.
2016 — 9.8 percent turnovers — 39.9 percent scoring opportunities.
2017 to date — 16.7 percent turnovers — 29.6 percent scoring opportunities.
In a continued effort to offer kudos where kudos are due … This concept was sparked by a conversation with an old drinking buddy first mentioned in a January introductory letter. From here on out, let’s refer to him as Harry.
“The stathead in me wonders what the rate of turnovers per defensive snaps is this year,” he pondered.
A valid thought, but a turnovers-to-snaps measurement would be an inherently-flawed metric. A turnover would not only increase the first half of the ratio, but it would also decrease the latter half by immediately reducing the number of coming snaps. Thus, turnovers-to-possessions should offer a more accurate depiction of the defense’s nose for the ball.
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