The Best Team Doesn't Always Win the World Series (but it did this year)

The American theoretical physicist, Leonard Mlodinow, has noted in his wonderful book, The Drunkard's Walk: How Randomness Rules Our Lives, that a 7-game World Series isn't long enough to absolutely guarantee that the best team will win. He notes that

if one team is good enough to warrant beating another in 55% of its games, the weaker team will nevertheless win a 7-game series about 4 times out of 10. And if the superior team could beat its opponent, on average, 2 out of 3 times they meet, the inferior team will still win a 7-game series about once every 5 match-ups. There is really no way for a sports league to change this. In the lopsided 2/3-probability case, for example, you’d have to play a series consisting of at minimum the best of 23 games to determine the winner with what is called statistical significance, meaning the weaker team would be crowned champion 5 percent or less of the time. And in the case of one team’s having only a 55-45 edge, the shortest significant “world series” would be the best of 269 games, a tedious endeavor indeed! So sports playoff series can be fun and exciting, but being crowned “world champion” is not a reliable indication that a team is actually the best one. (p. 70-71)

Mlodinow's a very smart guy, and I have no reason to doubt that his math is correct. That said, I think we're safe in assuming that this year's World Series winner, the Boston Red Sox, were the best team ("The 2018 Red Sox Are Baseball’s Best Champions Since The 1998 Yankees"). They won a franchise-best 108 games during the regular season, and took 11 out of the 14 games they played during the playoffs. Nevertheless, there was no guarantee that they'd win the World Series, and after Yasiel Puig put the Dodgers ahead 4-0 in the 6th inning of the 4th game, I thought there was a real chance the Dodgers just might pull off the upset. But at least this time, randomness didn't step in and ruin the Red Sox's amazing season. Instead, Dodger manager Dave Roberts did ("Dave Roberts Does it Again"). He pulled Rich Hill, the Red Sox came back, and the rest (as they say) is history.