The ELO ratings and regional winners:  Now that all 256 regionals in the endless single elimination tournament are under my belt, with 2,041 different teams participating, there is a decent sample to examine whether ELO ratings for the history of MLB can provide any indication of who will win a regional in this crazy single-elimination tournament.  And, the final answer seems to be:  kind of.  As shown in the chart, the modal ELO seeding for the regional winner is indeed the top seed, but that favorite only won 22.3% of the regionals, which is considerably better than the 12.5% we’d see if winners were entirely random but certainly not a sure thing.  If your team is in the top half of entries in the regional, you are more than twice as likely to win as if you’re in the bottom half, but for some reason #2 seeds didn't do all that well.  However, the squads that fare most poorly are the #7 seeded out of the eight teams–the worst ELO-rated team in these groups wins the regional more often than the second-worst, although neither would be a great bet.  The #4 seeds were strangely successful, which has nothing to do with pairings because in this tournament the team matchups were entirely random rather than being based upon seeding such as is done in, for example, the NCAA basketball tournament.  If the pairings had been based on seedings with #1 always playing #8 in the first round and so forth, things might have gone differently.  However, when I started this tournament in 1980, Arpad Elo had only published his book on his rating system (for chess players) two years previously, so his system wasn’t comprehensively applied to baseball until several years after my first tournament games were played!  A final note:  the source that I’ve relied upon for MLB ELO ratings was bought out by Disney, which resulted in mass layoffs and resignations, so I've had to rely upon other sources for the past few years of rankings, which might have used different calculations for the ratings.   Regardless, we can see that as the tournament heads to the super-regional rounds, there aren't a lot of really bad teams remaining alive (28 seventh or eighth seeds, compared to 57 top seeds), but there are still plenty of mediocre squads around to cause havoc!