Not an exact science, but often correct.
Virginia was #36 class last year. UCONN was not even top-75. BYU was #62.
In 2013, Viriginia was #34 and BYU and UCONN were #73 and #72m right ahead of UCF.
Some schools ranking are undervalued and other overvalued as there is a bias built in to the system, especially regionally, but program specific in particular. But it still is proven fairly accurate as to overall program strength. Even if it misses on some individuals from time to time.