Despite high-major protestations, the Missouri Valley Conference has not cracked any sort of mystical RPI code that has allowed six of its teams to reside in the top 45. Rather, the secret to the Valley's success is twofold. One part mostly anyone who follows hoops understands. The other, I'm not sure anyone does.
The bulk of the Valley's RPI surge has come the old-fashioned way: smart nonconference scheduling combined with lots of wins in those games. Anyone who follows college hoops and the RPI recognizes this recipe -- it's just usually followed by megaconferences with the word "Big" in them. The result: The Valley had a bunch of teams enter league play with gaudy records and strong RPIs, and the parity in the league helped preserve them.
The kicker that helped create the Valley's "RPI perfect storm," though, comes from the highly flawed adjustments the NCAA made to the RPI formula last season.