"So despite comprising less than 1 percent of all recruits, five-stars accounted for a quarter of 2015 first-rounders. Meanwhile, more than 90 percent of all recruits are designated as being three stars or less, yet their representation in the first round is nearly half that.
Put it this way: About one in four five-star recruits like No. 1 pick Jameis Winston goes on to become a first-rounder, but only about one in 64 three-star recruits like No. 2 Marcus Mariota does. Any generalizations about star-ratings that use NFL rosters as justification are giving disproportionate weight to the outliers."
There's a lot of good info here:
http://www.foxsports.com/college-football/story/signing-day-recruiting-rankings-5-stars-rashan-gary-derrick-brown-demetris-robertson-020116