There is an expression for someone whose shiny exterior hides a lack of substance: all hat, no cattle. The NCAA tournament has unmasked the Mountain West Conference as just that breed. Ranked the nation's best basketball conference according to its Ratings Percentage Index, the Mountain West sent a record five teams to the tournament…and went 2-5. That record includes losses to four teams seeded 12th or worse.

The Mountain West's five tournament teams were all ranked in the RPI's top 44, a measure that heavily weighs opponents'...