What is complementary football?

It’s been around forever but boils into the symbiotic nature between all three phases of football: offense, defense, & special teams. Tedy Bruschi described an example about seven years ago where New England pinned the Jets inside the 10, held them to a three & out, and then took advantage of a short punt to punch the ball in after converting two third downs into firsts.

Iowa’s had many situations where we’ve seen all three (sometimes just two!) lead to a score. My favorite in recent memory was how the Hawkeyes came out of halftime against the Cyclones last season.

The Hawkeyes took over at their own 10 yard line after ISU’s opening drive. A stellar punt - but really is was poor fielding of the punt - reflipped the field. Iowa moved the ‘clones back on the drive with three tackles for loss. Buoyed by a 24-yard punt return, the Hawkeyes then got moving on offense before a sack forced a punt. Though Iowa pinned State, forced a fumble, and took it to the house next drive, it shows how that hidden yardage can really impact a game vis a vis all three phases.

Unfortunately what was absent from much of this sequence was competent offense or, more appropriately, a string of competent offense enough to result in a touchdown.

And that’s the rub with complementary football at Iowa. Too often it seems used to excuse poor performance on offense, which is what this column looks to examine ahead of this season.

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But first, let’s examine how well Iowa has done the last five years in complementary football. While my selection of statistics is subjective, I hope it provides an objective measure to show how good or bad Iowa is doing, or has done, on their own terms. I’ve weighted the following components as such.

50% - Winning / Win percentage: I’m not a monster. If Iowa wins the game, enough was done on offense to justify the result. Week to week, this could result in some pretty wild variance but in aggregate it does the job.

33% - equal parts turnovers, time of possession, and offensive touchdowns: This is largely through the lens of “is Iowa’s offense helping the defense?” By limiting turnovers & holding onto the ball, it presumably keeps Iowa out of precarious positions in terms of field position and depth. Offensive touchdowns is shown as a way of answering whether Iowa’s offense takes advantage of opportunities given to them. Ideally, I would do red zone touchdown percentage but there were data integrity issues there which don’t exist with the simple “offensive touchdowns” metric. Plus, it seems silly to count a TD at the 20 yard line but not at the 21.

17% - equal parts third down conversion percentage, yards/carry, completion percentage, & QB sacks: Three of these four were outlined in a post ahead of the season by Scott Dochterman. His fourth, red zone TD percentage, is explained above. I’ve added QB sacks as it is a way to estimate offensive line ability. Ultimately, I believe these four are the most stylistic of the eight I’ve identified so they’re weighted the lowest. By the way, smarter people than I say that third downs are bad - which is true! - but for a team like Iowa built on sustained drives, an ability to convert on third down is paramount.

Some additional notes on the data: all of it is pulled from teamrankings.com, an elite website. The way the stats are compiled are simple win percentage and then the percentiles for each of the other ones vs. all NCAA FBS teams. Data is done for games between just FBS opponents so next week’s will be an estimation followed by data developed

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The best teams are the best at complementary football

In pulling the five-year dataset, I filtered to only Big Ten teams, which are represented by the 70 dots below. Iowa football peaked as a complementary football outlet in 2018 before dropping off since then.

Obviously, the metrics I’ve compiled show better teams (Win Percentage) have better statistics as they relate to complementary football. This is not rocket science. But it does show that the stats I identified are not the be-all-end-all for a given season as Iowa’s winning percentage has exceeded 2018 in each of the last three seasons. However, the dropoff in CFA aligns with the sense that Iowa’s offense has moved backwards since topping out with two first round tight ends. They have leaned even more and more on defense to squeeze juice from the rock.

But last year’s team entered into an unsustainable level under-reliance on offense for its complementary football. The only other teams to have complementary football aggregates (CFA) under .4 and winning records are: Michigan State in 2018 & 2019 and Penn State last season. The remaining 19 teams had an average winning percentage of 29%! That’s not good! (Overall the group under .4 averaged a 34% winning percentage)

Contrast this with the outlier who had a strong CFA but sub .500 winning percentage. That was the 2020 Minnesota team. In fact, each of the last three Golden Gopher iterations have been above the best Iowa football team in terms of CFA. This is the crux of my frustration - while Iowa wins, they fail to execute on offense the identity they were most known for throughout the aughts: “Bullies of the Big Ten.”

This isn’t to say that Iowa doesn’t stuff PJ Fleck and others into lockers when those matchups come around but they do it largely through defense and not on offense.

This is the exact same data framed a slightly different way. First it assigns teams to each of the dots but also allows trends across teams to be gathered. Penn State and Wisconsin? Trending down alongside Iowa. Purdue? Trending up. Ohio State? Death star.

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To wrap this thing up, I went ahead and ranked each season based on that total number. I then identified tiers (described below) to each of the seasons. Among each team’s five seasons, I took the median. They look as such:

S ( > .85): Ohio State
A ( .70-.85): N/A
B (.60-.70): Iowa & Wisconsin
C (.50-.60): Michigan, Minnesota, Northwestern, & Penn State
D (.40-.50): Indiana, Michigan State, Purdue
E (.20-.40): Illinois, Maryland, Nebraska, Rutgers
F (< .20): N/A

Perhaps nothing sums up Iowa football better than this. Even though they struggle in areas I’ve identified as necessary to a successful complementary offense, they find themselves continuing to win. Only Ohio State & Wisconsin have demonstrated a better ability to maintain consistency in the complementary football areas alongside stacking wins.

Yet the razor’s edge Iowa operates on puts them in a position where the current trend is unsustainable as a path towards victory. Tomorrow will be the first indicator as to whether Iowa will continue the decline or show that 2021 was rock bottom’s basement.