The Cubs are good #hottake
This is the blog post that I would have written after the Cubs 30th game when they were 24-6 if I wasn’t in bed 20 hours a day for the last week with “the sickness”. Anyway, I scraped baseball reference to get the game results of all teams going back as far as they go. First I looked at how may teams had started 24-6 or better in their first 30 games. The list is here:
^ – Lost World Series
* – Won World Series
Pittsburgh 1902 (No World Series in 1902)
Chicago Cubs 1907*
New York Yankees 1928*
New York Yankees 1939*
New York Yankees 1958*
LA Dodgers 1977 ^
Chicago Cubs 2016 ?
(Note: Chicago White Sox 1912 (23-6-1))
Prior to the 2016 Cubs, 11 teams since 1902 have started 24-6 or better. In one of those years there was no World Series (1902), so considering the 10 teams that started 24-6 or better and there was was World Series that year, 7 of those teams made it to the World Series with 5 out of those 7 teams winning the World Series. So professionally I’m not saying that the Cubs will make the World Series, but personally I am guaranteeing in.
Next I wanted to to look at the relationship between teams winning % after 30 games and there winning % at the end of the season. The plot below shows a scatter plot of this.
No team has ever finished the season with a winning percentage over .800. The highest winning percentage ever was the 1906 Cubs with a winning percentage of 0.758 (116-36-3). More recently the Mariners in 2001 finished with a winning percentage of 0.716 (116-46).
I also fit a simple linear regression line through the data and the fitted values are as follows (red line on the scatter plot):
This model predicts that the Cubs will win, on average, 103.41 games this year based on their first 30 games with a 95% prediction interval of (84.58, 122.24). That’s probably not that interesting of an interval so I also looked at a 50% prediction interval which ended up being (96.93, 109.89). This means there is about a 50% chance that the Cubs end up with wins in this interval. Further, it also means that there is about a 1 in 4 chance the Cubs end up with fewer than 97 wins, but there is also about a 1 in 4 chance that the Cubs win MORE THAN 110 games.