So The Ringer went and broke the optimism embargo with "Curses Don't Exist: The Chicago Cubs Are Winning the 2016 World Series."
Mark Titus is right! Curses don't exist. Not even the Curse of Bartman Being Treated So Shabbily By Greater Chicagoland, which if I believed in curses, would be the one I believed in. But I am a fatalist and do believe the fates tend to be aligned against us, and the numbers tend to bear that out. So there's reason to be skeptical of the Cubs' chances in the playoffs, not because of anything they've done wrong (they've done an impressive job assembling the team) or because other teams are better (they're not).
The first is one of my favorite uses of sabermetrics ever: how good would a baseball team have to be to be statistically favored to win the World Series? In the abstract, the answer is really, really good. As Russell Carleton explains, they'd have to have an 80-percent chance of winning each series, which means a 65 percent chance of winning each game they played:
Using the log5 formula for predicting the chances in one specific game, we can plug in .65 as our expected outcome and .555 for the opponent's win percentage. What sort of team would be needed to maintain a 65 percent chance of winning one game against a 90-win team. Doing some algebra, the answer is actually just shy of a .700 winning percentage.
That translates into a regular season record of 113-49. A team would need to be on par with some of the all-time greats before we would consider them to be even a 50/50 shot to win the World Series.
The Cubs have a .650 winning percentage, and that's underselling how good they are. Their run differential is a ridiculous +229, or eighty-seven runs more than the second-place Red Sox (who, if you were wondering if baseball is fair, aren't in first place in their division). If you want to use that as a measurement of how good they actually are, they're actually around a .700 team.
So as good as the Cubs are, the best we can say is that they have around 50/50 odds of winning the World Series. Right now Baseball Prospectus gives them a 23.4 percent chance of winning it all. That's really good. But it's still pretty low.
But that's in the abstract. How well have the best teams in baseball fared in the playoffs?
Not well. In 2013 Julian Ryan and Barrett Hansen of the Harvard Sports Analysis Collective looked at the four major sports to determine how often "undeserving" teams win championships in their respective sports. The NBA is the most fair in this sense—by both measurements of team quality they used, the mean rank of the championship team from 1995-2003 was 3.3. They make a good point: there are a lot of possessions in an NBA game, which means there are, cumulatively, many more competitive moments than in the other sports. Perhaps for the same reason, hockey is second by both measures.
You might think that football would be the least fair, given its one-and-done playoff format. No:
What is remarkable is just how bad the MLB playoffs really are…. If you chose the eight best regular season teams, or even eight of the top ten because you require four from each league, and then just asked each team to draw straws to determine the World Series, the average winning team would be better determined than by the current system. Only three times has the best team from the regular season ended up winning the World Series.
And the least deserving team in any of the four sports over those 18 years? A Cardinals team, of course, which went 83-78 in 2006 and was, by the Simple Ratings System, the tenth-worst team in baseball that year.
The Cubs are about as well positioned as a team can be to win the World Series, but that will only take you so far—realistically speaking, about coin-flip odds. Anything can happen, and anything is more likely to happen in baseball than in any other sport.