*Note: All data is from the 1985 tournament to the present.
The number of upsets by No. 13 seeds over No. 4 seeds have decreased recently. The No. 4 seed has an .803 winning percentage and in three of the last four years, all four No. 4 seeds have moved out of the first round.
Last season was a fairly productive tournament for No. 4 seeds. Florida made the Elite Eight in the East region after knocking off Wisconsin on Chris Chiozza's buzzer beater in the Sweet 16. The other three No. 4 seeds – Purdue, Butler, West Virginia – each advanced to the Sweet 16 before falling to the No. 1 seeds in their respective regions.
Louisville owns the most appearances as a No. 4 seed. The Cardinals maintain an 8-1 first-round record, with the lone loss in a 2011 thriller to Murray State. Two of Louisville's wins were by 19 points and 22 points but the rest were decided by single-digits including a two-point win over UC Irvine in 2015.