It's all based on Strength of Schedule. USC has Arkansas and Nebraska helping them out a great deal, plus their worst games are their bottom Pac 10 opponents, which are still usually rated higher than most teams non-conference schedules (their entire non conference schedule is Arkansas, Nebraska, and Notre Dame-of course Notre Dame doesn't factor in to their schedule so far). Ohio State though has one great opponent so far-Texas. Other than that, Penn State, Iowa, and Michigan State all have at least 3 losses, and they have Northern Illinois, Cincinnati, Bowling Green, and Indiana. Ohio State's schedule has not really been all that hard. Michigan is ahead of OSU for one basic reason-they both have played one great opponent (OSU-Texas, Michigan-Notre Dame), they both have several common games (Iowa, PSU, Michigan State), similar other non-conference games (OSU-Cincy, Bowling Green, Northern Illinois, Michigan-Vanderbilt, Central Michigan). So it basically comes down to their other conference games-and Michigan leads by having played Wisconsin. ND shouldn't be considered a great opponent.