I recently looked at the history of teams to make a significant improvement from one year to the next and found that many of them win fewer games the year after their breakthrough season. This suggests that the Bears might be due for a bit of a letdown from their 12-4 record in 2018 (though they do match the profile of teams that generally stay good after making the jump.)
Today, I want to look more closely at Chicago’s underlying performance in 2018 to see if there’s anything there to suggest they are a team poised for a fall. This is closely modeled after work Bill Barnwell does every off-season, where he uses three factors to identify teams who are likely to improve and likely to regress.
The first factor is called the Pythagorean expectation, and it is a measure of how many games a team is expected to win based on how many points they scored compared to how many points they allowed. The exact formula can be seen here, but the general idea is that truly good teams score a lot more points than they give up. Teams that win a lot of games without a large difference in points scored/allowed were considered more lucky than good and are likely due for a fall.
- 2018 Bears stats: 421 points scored, 283 points allowed, 12 wins
- 2018 Pythagorean expectation: 11.5 wins
The Bears didn’t significantly outperform their Pythagorean expectation, which means they won a lot of games because they were legitimately good, not lucky. So far, there is no reason to think that significant regression is coming.
Record in Close Games
The 2nd factor looks at how well teams performed in close games, which Barnwell defines as having a final scoring margin within 7 points. I think 8 points makes a lot more sense given that’s still a one possession game, but in this case it doesn’t change anything for the Bears, so we’ll stick with 7.