Chicago’s defense was really, really good in 2018. They led the NFL in points allowed, turnovers forced, touchdowns scored, and passer rating against, and finished 3rd in both yards and sacks. They finished as the runaway best defense in Football Outsiders’ DVOA, which is intended to be an all-encompassing metric, and even finished as the 12th best defense ever in DVOA’s database, which runs back to 1986.
Now as we head into 2019, fans are rightly wondering if Chicago’s defense can repeat that performance. While I won’t pretend to be able to predict the future, I can look at the past to see what it might have to tell us.