2025 College Football Analysis, Part Three: Big Ten Odds and Strengths of Schedule

So far in this year's math-driven college football preview, we have explored the historical accuracy of the preseason rankings, taken a look back at 2024 and conducted a thorough analysis of the potential paths for the 2025 Michigan State Spartans' Big Ten and overall season.

In today's installment, the focus shifts to the Big Ten conference race.

Strengths of Schedule

The first thing to cover today is relative strength of schedule. Figure 1 below summarizes my calculations for the 18 Big Ten teams' overall schedules.

Figure 1: Overall strengths of schedule for the 2025 Big Ten conference. The overall FBS rank is shown in each bar.

There are several different ways to calculate strength of schedule. I use my preseason estimations of power rankings to generate estimated point spreads for all potential college football matchups. I then calculate the number of expected wins that a reference, borderline top-25 team would have if that reference team were to play the schedule in question.

For example, if the reference team were to play Michigan State's schedule, that reference team would have an expected win total of 7.62 games (0.635 win percentage). That grades out to No. 7 amongst Big Ten team and No. 22 toughest nationally (as indicated by the label on the bar in Figure 1). It is slightly easier than the Spartans' schedule in 2024 (7.11 games and No. 15 nationally at the end of the year.)

Note that Illinois, Indiana, Minnesota and Nebraska all have schedules outside of the top-50 nationally in difficulty. Ohio State, Iowa, UCLA, Northwestern and Purdue all have top-20 schedules. while Wisconsin overall owns one of the most difficult schedules in the nation at No. 8.  The difference between the easiest and hardest schedule is close to two full games, 1.83 wins out of 12 total. 

Figure 2 below gives the same calculation considering only the nine Big Ten conference games.

Figure 2: 2025 Big Ten football conference strengths of schedule. The horizontal line represents the conference's average difficulty.

Illinois (5.96) and Michigan (5.93) drew the two easiest conference schedules this year, both of which project to be over a half-game easier than the conference average (5.3). Both teams are considered serious contenders in the Big Ten race this year.

Outside of Michigan, the other three primary contenders are Penn State (5.22), Ohio State (5.36) and Oregon (5.35). Those teams all draw schedules that are within a tenth of a game of the conference average. Penn State nominally has the most difficult schedule of any of the Big Ten contenders.

Outside of Illinois, the other three dark horse contenders are USC (5.69), Indiana (5.55), and Nebraska (5.69). All three of these teams have schedules that grade out slightly easier than the conference average.

The most challenging conference schedules in 2025 belong to Rutgers (4.82), Northwestern (4.8), Michigan State (4.79) and especially Wisconsin (4.63). Note that the teams with the easiest Big Ten schedules (such as Michigan) have over a one game advantage over the set of teams (such as Michigan State) with the hardest schedules.

For reference, Table 1 below summarizes the overall and conference strengths of schedule for the teams with the top-50 toughest schedules nationally using my calculation method. In this case I have converted the strength of schedule metric to win percentage due to the differing number of conference games played across the country.