Meh, I don't think the defenses of Penn St, Michigan, Ohio St, or Iowa are ranked where they are because of poor offensive competition. Not to mention you can make the same case for most of the QBs in the SEC. Some of you guys hold the SEC in way too high esteem. They aren't the only conference with talent.
Idk, it's a pretty big difference in stats when they face those 3 vs not.
Iowa didn't face any of those top 3 QBs, so can't compare their numbers, but for Mich, OSU, and PSU, here are their combined passing defense splits when playing against those three vs others:
Overall, 36 combined games:
528 of 964 (54.8%)
5,477 yards (152.1/game, 5.7/attempt)
22 TDs
35 INTs
102.8 QB Efficiency
vs McCarthy, McCord, and Tag, 7 combined games:
134 of 204 (65.7%)
1,494 yards (213.4/game, 7.3/attempt)
7 TDs (1/game)
7 INTs (1/game)
131.7 QB Efficiency
vs all others, 29 combined games:
394 of 760 (51.8%)
3,983 yards (137.3/game, 5.2/attempt)
15 TDs (0.5/game)
28 INTs (1/game)
95.0 QB Efficiency
And when you take out the games vs the only three significant non-conference QBs they played (Hartman at Notre Dame, Brecht at Iowa State, and Greene at West Virginia) the split is even wider, as they had better-than-average games, as well.