On the first full weekend of this college football season, with fans in the Camp Randall stands for the first time since 2019, Penn State and Wisconsin played the kind of game their conference does best — a 16-10 defensive struggle. Neither team scored in the first half, and only three drives crossed midfield in that span. Wisconsin possessed the ball for more than 42 minutes and rushed 58 times, but the Nittany Lions prevailed, thanks largely to a goal-line stand in the final minutes.

Over the past two decades, the scoring pace in college football has trended mostly upward, and yet the Big Ten seems unaffected. It continues to produce some of the country’s top defenses: This season, for the third straight year, the Big Ten has three of the top 10 scoring defenses — No. 2 Iowa, No. 3 Penn State and No. 6 Michigan — and three of the top 10 in yards allowed per play (No. 4 Iowa, No. 7 Wisconsin and No. 9 Penn State). The standard bearer this fall is Iowa, which began the season with games against two ranked opponents and stifled them both, holding Indiana to 6 points and Iowa State to 17. The Hawkeyes forced seven turnovers in a rout of Maryland last week.

In 2015, when the national scoring average at the FBS level was 29.57 points, Big Ten teams allowed an average of only 24.97 per game. That was the year Jim Harbaugh started as the head coach at Michigan and Paul Chryst debuted at Wisconsin. Both teams ranked in the top five in yards allowed per play in 2015, and Wisconsin led the country in allowing 13.7 points per game. When the teams met on the field Saturday, neither reached 5 yards per play on offense, and Michigan won 38-17.¹

Six years later, even as offenses find new ways of deploying faster players, Big Ten defenses are still thriving. Since 2015, the Big Ten is the only conference whose defenses have allowed a negative expected points added per drive. Opponents score just 1.81 points per drive against Big Ten teams, with touchdowns on only 22.4 percent of possessions — both national lows. In the same span, the conference’s defenses have allowed 5.3 yards per play, including 6.7 yards per pass and 4.1 yards per rush, best among all FBS conferences.

The Big Ten’s stout defensive numbers translate to a perception that the conference simply has better players on that side of the ball. Since 2016 (the year after Chryst and Harbaugh arrived), the SEC has dominated all of its peers on offense at the NFL draft with 165 picks — far ahead of the Big Ten’s second-best 107. But on defense, that gap is more narrow, with 172 picks for the SEC and 140 for the Big Ten. In those six drafts, only 23 wide receivers have been selected from the Big Ten, half of what the SEC produced, but 27 defensive ends, besting all competitors.

What makes the Big Ten so stout? Its teams have excelled at the building blocks of defense. From 2015 to 2020, Big Ten teams were successful on 92.7 percent of all tackle attempts, the best rate among Power Five conferences. On play-action, Big Ten teams allowed the lowest rate of successful plays² among all FBS conferences. And even though they didn’t blitz with unusual frequency, Big Ten defenses pressured opponents more often than any other conference except the SEC, on 31.2 percent of dropbacks.

In a defense-driven conference, nobody has been stingier this season than Iowa, which ranks No. 3 in both major polls this week despite its paltry 4.8 yards per play (114^th in the FBS). The Hawkeyes may not keep up their dominance without an infusion of offensive firepower — since 2004, only three teams have finished in the AP top 10 with less than 5 yards per play offensively, and the least prolific of the three was Iowa in 2004, with a 10-2 finish. But in this day and age, the Hawkeyes do make a fine representative of the Big Ten’s strength.

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