For those into the advanced stats, here are the preseason SP+ rankings.

The formula factors in recruiting, recent history and returning production. It's the last category that is probably dragging OSU down to 7:

Returning production: Instead of using returning starters, I created a formula for returning production based on which units seem to have the most effect on a team's improvement or regression. As it turns out, continuity at quarterback, receiver and the secondary is far more impactful on SP+ rating the next year than continuity in other units. Accordingly, turnover in those areas takes on heavier weight.

These have tended to be pretty accurate over the course of a season, though they obviously get better as the sample size gets bigger.

In a separate article he breaks down the ratings by conference. Big Ten checks in at #2, and the Big Ten East as the third-toughest division.