As I was working out the other day, I (sadly) had on ESPN and they were doing their bracketology thing. The subject was how to fill out your brackets, and who might be the bracket busters this year.
The talking heads spoke of the many 12 seed vs. 5 seed upsets that we have had in years past and started diving into insane statistics, advanced mathematical models, and a whole bunch of other bullsh1t to try to explain not only the 12 and 5 upsets, but others as well.
As this was going on, I simply laughed at them as I knew full well why we have had 12 vs. 5 upsets in the past, and will likely see more 12 vs. 5 upsets in the future (assuming our current conference setup - bear with me and you will see why).
Seeds 1 through 47 comprise large conference champion winners and a bunch of "at large" bids. The teams that fall below seed 47 are all conference champions of tiny conferences that nobody for the most part has heard of. However, some of these conferences are "mid majors". Do you get it yet?
Seeds 1-11 in the brackets are all teams from large schools. Some of these schools have crap teams (this year see UCLA and Indiana) but have large alumni bases that bring fans and money - hence they make the tournament. Most teams that fall below the 11 seed have all won their conference tournaments and are "hot" and in some cases damned good teams to begin with. I am not saying that they can beat the Kentuckys of the world, but put against a team that could be mis-seeded, they definitely have a chance.
4 regional bracket x 12 teams = 48. The 5 vs. 12 seed is pitting the very best of these smaller teams that are hot against perhaps a middling school that could or could not be mis-seeded. This is the best chance that any small school has to pull an early round upset.
It isn't wizardry or luck, it is just math, plain and simple. And the talking heads dive deeper into the rabbit hole wondering why this happens. Over and over and over.