8 seed (Oregon). The eye test. Strength of conference. Lack of impressive wins that you would expect from a 5 seed.
Clearly the committee thought the Pac-12 was stronger than most non-West Coasters believed, as evidenced by inviting UCLA and giving them an 11 seed with no play-in, and giving utah a higher seed. Of course, given the Pac's performance in the first two rounds, the committee wasn't completely out to left field about the conference. Nevertheless, I thought the utes merited a 6 or 7, as I was saying going into Selection Sunday. I would have swapped utah and Michigan St, which I felt was clearly under-seeded -- and subsequent events bore that out.