How good does Iowa's defense need to be for the Hawkeyes to win? Here's what the data says

IOWA CITY — Iowa’s defensive line room had a discussion on Tuesday morning about self-awareness.

The conversation was another way in which Iowa’s defensive line coaches “do a great job of bringing the real world in to us,” defensive end Deontae Craig said. The timing was especially apt three days after Iowa’s defense allowed 468 yards to unranked Michigan State.

“Really where it’s tested is when you turn on the film,” Craig said of self-awareness. “Because people can lie all they want to, but the tape never lies. So what you put on tape is what you have to live with and what you have to explain. … It’s obviously difficult, especially when you know you didn’t do your best.”

Iowa had 32 consecutive football games of allowing fewer than 400 yards — the longest streak across the country while it was active — until its 35-7 loss earlier this month to Ohio State. Iowa has now given up 400-plus yards in two of the last three games. (Washington was not far off either with 393 total yards.)

Iowa’s 20 missed tackles against the Spartans, as tracked by Pro Football Focus, certainly did not help matters. Michigan State gained 138 rushing yards after contact and 123 receiving yards after the catch, per PFF.

“We’re in a situation where I think you got to remind yourself that we have played real good football defensively, and we have tackled well,” said Seth Wallace, Iowa’s assistant head coach and linebackers coach.

Despite the rough showing in East Lansing, Iowa’s defense still is statistically above par, ranking 44th nationally in yards allowed per game and 57th in yards allowed per play. The Hawkeyes have allowed 5.3 yards per play while the FBS average is 5.5 yards per play.

While still above par, Iowa’s defensive numbers do mark a deviation from the formula Coach Kirk Ferentz’s program has relied on in recent seasons — an elite level of play on defense and special teams making up for substandard offensive production. Iowa led the country in yards allowed per game in 2022 and 2023 (and was in the top 10 in 2021) as it claimed Big Ten West titles in two of the last three years.

The good news for Iowa is its offense has improved drastically — from 15.4 points per game in 2023 to 27.9 in 2024. That’s not enough of an improvement, however, to mask a defensive letdown like what Iowa experienced against Michigan State.

When Iowa has allowed more than 5.5 yards per play this season, the Hawkeyes are 0-3. When allowing fewer than 5.5 yards per play, they are 4-0. (The Hawkeyes allowed 6.7 yards per play against Michigan State, 6.3 yards per play against Ohio State and 5.6 yards per play against Iowa State.)

Essentially, Iowa’s defense does not necessarily need to be elite, but it at least needs to be better than the FBS average of 5.5 yards per play for the Hawkeyes to have a decent shot at winning.

It is hardly a new phenomenon. In Iowa’s last 48 games, dating back to the start of the 2021 season, the Hawkeyes are 1-6 when allowing more than 5.5 yards per play. When holding opponents to less than that, they are 31-10.

The one game where Iowa allowed more than 5.5 yards per play and still won was in 2022 against Minnesota, when the Hawkeyes benefited from the Gophers’ fumble, interception and missed field goal.

Looking ahead, improved tackling obviously would go a long way toward putting the Hawkeyes in the situation where they’ve been 31-10 rather than 1-6.

“I used the term ‘uncharacteristic’ on Saturday, and time will tell on that one, right?” Ferentz said of the missed tackling. “If we get it straightened out and improved and do things that we've been doing well, if we can get back on that plane, then yeah, it is uncharacteristic.”

Ferentz, perhaps modeling the self-awareness that the defensive linemen were talking about earlier in the day, also recognized it “could be the start of a trend.”

“Hopefully not,” Ferentz said.

Comments: john.steppe@thegazette.com

Sign up for our curated Iowa Hawkeyes athletics newsletter at thegazette.com/hawks.