For the first time since the expansion of the field to 64 teams in 1985, all four #1 seeds advanced to the Final Four. This may come as a surprise. How could it take 24 years for the best four teams to all make it to the semifinals? Well, if we take a closer look at the mathematics behind it, it’s not that strange.

Looking back over the 23 previous tournaments, a #1 has won its regional championship game 41.3% of the time. When you think about it, that seems reasonable, as you would think by the time a team reaches the Elite Eight, they will have to play a pretty evenly matched opponent. So, given that probability, in order to calculate how likely it is that all four of the #1 seeds advance, you have to raise this number to the fourth power. When you do that, you get about a 2.9% chance that the Final Four is comprised of all #1 seeds, which translates to once every 34 years. This is the 24th year, so it is not too surprising it took as long as it did.

Perhaps a bit more interesting is if you look at the probability that no #1 seed advances to the Final Four. Here, we get that the probability a top seed does not advance to the Final Four is 58.7% (100% - 41.3%, see?). When raised to the fourth power, we get that the chances that no #1 seed is a Regional Champion is 11.9%, which means that about twice every 17 years, we should be without a #1 seed in the Final Four. However, this has only happened once in the 24 year history since the expansion, when #11 seed George Mason joined fourth seeded LSU, #3 seed Florida, and #2 seed UCLA.

What does this all mean? Perhaps our sample size is too small, but I have a feeling this is not the case - if anything it is getting tougher for #1 seeds to advance as the parity in college basketball grows. Instead, I think it is more of a sign that there is not much difference between a #1 seed and a #2 seed. Despite the fact that a #2 seed’s chances of reaching the Final Four is 21.7%, they match up very evenly with the top seeds. Coming into this year’s tournament, when the #1 seed has played the #2 seed with a place in the Final Four on the line, the record for the top seed is 16-16, exactly 50%.

Most years, there are somewhere between five to eight teams who go into Selection Sunday feeling they have a legitimate claim to a top seed. So it is not surprising that when they face off with each other, the rank becomes irrelevant. This year, however, was different. The top four teams were a class apart for most of the season, each team winning both their respective regular season title and conference tournaments, and have only nine losses combined. And considering the struggles that the second-seeded teams had, it made the road to San Antonio a little easier. Will it happen again that all four top seeds make it to the Final Four? Probably, but we might have to wait 34 more years.