March Madness bracket trends show that the longshots of the NCAA basketball tournament are the 13 through 16 seeds. It's a huge achievement for one of these high seeds to make the Sweet 16. In fact it's only been done six times, four by 13 seeds and two by 14 seeds. No team seeded higher than 12(Missouri in 2002) has ever made it to the Elite 8.
13 thru 16 seed March Madness bracket trends since 1985:
Number 13 seeds are 18-74 against 4 seeds
Number 14 seeds are 15-77 against 3 seeds
Number 15 seeds are 4-88 against 2 seeds
Number 16 seeds are 0-92 against 1 seeds.
The summary below shows how far 13 thru 16 seeds have made it in the NCAA tournament since 1985: