Every baseball fan, and a lot of people who aren't, know the Chicago Cubs haven't won the World Series in a really, really, really long time. The Cubs' play-off flame-out last fall made it a nice round 100 seasons since their last title in 1908. Clearly, this is a signifier of some level of ineptitude over the years. The chances of winning the World Series in any given year are pretty small though. Maybe there is something more than ineptitude at play here; like bad luck.What are the chances that any team, given a fair chance every year, would not win the series in 100 years? Well, let's play it out. In 1908, there were sixteen major league teams, which logically are the only teams eligible to go 100 seasons without a title. I simulated each season, starting with 1909. And by simulated, I mean a winner was randomly chosen, remember every team has a fair and equal chance to win. This fair and equal chance to win gets smaller as the years go on however. Subsequent expansions to 18, 20, 24, 26, 28 and 30 teams and the resulting increased competition are factored for. Then after all 100 seasons are simulated, titles are counted up for each team. Repeat 250,000 times or so and then sum the number of occurrences when a team went without a World Series title. As it turns out, the average is a hair over .08 teams that fail to win a Series in the 100 seasons. Or, if we repeated the last 100 years, there is about 1 chance in 12 that any team would match the Cubs' feat.
Clearly, considering every teams' Series chances equal is a huge simplification of what's actually happening. There have been several factors that indicate that it is not a level playing field. The overwhelming success of the New York Yankees (26 titles) definitely indicates that certain teams have some sustained competitive advantage. And more recently, the unbalanced realignment of the American and National Leagues as well as the Cubs' Central Division has further shifted the probability of winning for certain teams. I repeated the above process but this time applying a varied, linear relationship to each teams probability of winning. In other words, the worst team was given (X-A)% chance of winning while the best team was given (X+A)% chance of winning with similar adjustments for the middle of the pack.
In this model, the worst team is assumed to be one of the original sixteen and the worst team is assumed to be the same year after year. Again, this model is imperfect and a great oversimplification however it does provide a frame of reference for what the Cubs have achieved or failed to achieve as the case may be. Even when assuming that one team has a huge and sustained disadvantage (specifically 1/3 to 1/20 the chance of the best team to win the Series), there is a less than three in ten chance that a team could go 100 years without winning the fall classic even once.
So what does this say about the Cubs? Yeah, they're still bad. Even if they epically sucked year after year without exception, there is only about a 30% chance they'd go without winning the series. However if they were much better and merely consistently average, there is still not a small chance that they could happen to not win. So yeah, they've definitely not been good. But they've definitely not been lucky either.
So what does this say about the Cubs? Yeah, they're still bad. Even if they epically sucked year after year without exception, there is only about a 30% chance they'd go without winning the series. However if they were much better and merely consistently average, there is still not a small chance that they could happen to not win. So yeah, they've definitely not been good. But they've definitely not been lucky either.

