No one ever said it was an exact science, but it has proven to be a pretty reliable science overall. So many human elements involved that can't always be accounted for.
Not basketball, but if Oregon wins the title this year, they'll be the first team since 2000 OU to win the football championshiop without having at least two top 10 ranked recruiting classes out of their last four.
The recruiting rankings aren't exact, but they paint a pretty good picture as a whole.