Useful material, especially for the "stars matter" crowd: Bud Elliott's blue chip ratio rankings.
Michigan clocked in here with a qualifying 57% ratio, 9th, right behind Clemson. FWIW Clemson had a relatively low 52% ratio when they won in the 2016 season; most winners recently have been higher.
The premise of this: Elliott asserts that teams who win the title recruit more 4-and-5 star recruits than 2-and-3 star recruits. Read the article for more details.
One important caveat: They ignore transfers, his logic being that they matter but usually do not have a huge impact on a team's ability to win, something that Shea Patterson has a chance to turn on its ear.