The veracity of the NFL’s “strength of schedule”
I’m no statistician, but I love data. And while I spend a little too much of my day with economic and marketing charts, I occasionally enjoy geeking out with other fun data.
And so when the NFL announced that my beloved Miami Dolphins would have the league’s toughest 2009 schedule, I sought reassurance in the numbers.
The NFL is notoriously topsy-turvy. Due to the high turnover of players, coaches, and team surgeons, about half of playoff teams this decade failed to return to the playoffs the following year. Given that, what exactly is a measure of “strength of schedule” as defined by opponents’ prior year won/loss records really worth?
Quite a lot, actually. I looked back at 2008’s strength of schedule rankings, as defined by opponents’ 2007 W/L percentages. Then I compared against how tough those 2008 opponents turned out to be, as defined by Football Outsiders’ amazing DVOA metric of team efficiency.
The sad-sack Browns, Bengals, and Lions ranked 1-2-3 in opponents’ DOA (partially because they never got to play themselves), but the Super Bowl champion Steelers were right there at #4. The Titans and 49ers’ schedules were significantly easier than projected, while the awful Raiders and Chiefs’ schedules were projected to be terrible and turned out average.
Overall, though, the correlation was uncanny.
That, my friends, is an r-squared of .534.
This season, the AFC’s best division in 2008 (the East) is scheduled to play the NFC’s best division in 2008 (the South), so the top eight slots for strength of schedule are held by those eight teams. Unmeasured in this metric are the details of the schedule. In addition to the #1 ranking of opponents’ 2008 W/L record, the Dolphins must play a Sunday west coast road following a Monday night home game (both against 2008 playoff teams), a Thursday night road game (against a 2008 playoff team) following a Sunday home game, a stretch of four road games in five weeks, and two outdoor cold-weather games.
And then there’s that r-squared.
Ah, who cares? This season is going to fun. Bring ‘em on.