As busted as the brackets are after the first round, there are surprisingly few upsets. By an upset I mean a lower seed defeating a higher seed, except when they are adjacent seed which are statistically tossups. I've been tracking upset rates since the early 1990's and I've found most years have around a 25% upset rate. The first round had only 5 upsets in 28 games (8 vs 9 games don't count). That's 2 less than last year which was right on average with 7 upsets in the first round, before jumping up to 5 upsets out of 14 second round games.
The second round had 3 upsets in 14 relevant games that could have an upset. The typical 25% would be 3.5, so 3 upsets is a statistically likely result. Combining both rounds there have been 8 upsets in 42 games for a rate of 19% - below historical averages but less so than after the first round.
