Game quality

What each result was worth beyond the score. Every play is graded by EPA (expected points added), then adjusted for who it came against: a defence's rating is what it allowed to everyone else that season, so a big day against a bad defence counts for less. Season views include playoff games.

Jordan Love — 2021

Adj EPA / dropback
-0.152
Raw EPA / dropback
-0.107
Dropbacks
66
Turnover EPA
-15.1
WPA
-0.37
WeekOpp DropbacksAdj EPA/dbRaw EPA/dbScheduleTotal adj EPA INT / FLTurnover EPASacksSack EPAWPACPOE
1NO 8 -0.149 -0.239 +0.090 -1.2 0 / 1 -5.6 1 -5.6 +0.00 +15.5
9KC 35 -0.050 -0.023 -0.027 -1.7 1 / 0 -3.4 1 -2.0 -0.16 -3.6
17MIN 4 -0.017 -0.037 +0.020 -0.1 0 / 0 +0.0 0 +0.0 +0.00 -21.0
18DET 19 -0.369 -0.222 -0.147 -7.0 2 / 0 -6.1 1 -1.9 -0.20 -14.2
Opponent adjustment. A unit's rating for a game is its average over its other games that season, blended with 16 games' worth of prior (league average plus half of last season's gap from it; 24 games for pass defence, which is noisier). Early in a season that leans on last year; by midseason it is mostly this year. Chosen by how well it predicts a held-out game: it cut that error by about a quarter against no shrinkage, and adjusted numbers agree between odd and even weeks more than raw ones do (team EPA margin r 0.52 → 0.55, defence 0.32 → 0.36, QB EPA/dropback 0.47 → 0.49, 2016–2025).
Win expectancy is a logistic fit of wins on EPA margin over 6,036 completed games (it names the winner 86.5% of the time). These describe what happened; one game is not a forecast. Play-by-play credits the quarterback with every sack and dropback, so a bad line shows up in his numbers. Seasons 2016–2026, built 2026-09-14 01:25 UTC, from nflverse. Write-up: backtests/nfl_game_quality/FINDINGS.md.