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.

Brock Purdy — 2024

Adj EPA / dropback
+0.158
Raw EPA / dropback
+0.162
Dropbacks
482
Turnover EPA
-65.9
WPA
+1.42
WeekOpp DropbacksAdj EPA/dbRaw EPA/dbScheduleTotal adj EPA INT / FLTurnover EPASacksSack EPAWPACPOE
1NYJ 31 +0.248 +0.210 +0.039 +7.7 0 / 0 +0.0 2 -2.4 +0.17 +1.2
2MIN 42 +0.057 +0.013 +0.043 +2.4 1 / 1 -9.2 6 -11.3 -0.06 +8.4
3LA 31 +0.462 +0.462 +0.000 +14.3 0 / 1 -3.1 1 -3.1 +0.20 +8.3
4NE 28 +0.223 +0.248 -0.026 +6.2 1 / 0 -4.4 1 -1.3 +0.07 +2.8
5ARI 37 -0.099 -0.024 -0.075 -3.7 2 / 0 -7.8 2 -2.9 -0.09 -2.8
6SEA 28 +0.411 +0.419 -0.008 +11.5 0 / 0 +0.0 0 +0.0 +0.14 +1.1
7KC 33 -0.315 -0.324 +0.009 -10.4 3 / 0 -13.4 1 -1.0 -0.36 -9.6
8DAL 28 +0.244 +0.261 -0.017 +6.8 0 / 0 +0.0 2 -2.3 +0.21 +2.9
10TB 38 +0.416 +0.443 -0.027 +15.8 0 / 0 +0.0 3 -3.5 +0.79 +8.7
11SEA 30 +0.010 +0.026 -0.016 +0.3 1 / 0 -4.9 2 -2.2 +0.18 +2.0
13BUF 19 -0.364 -0.341 -0.023 -6.9 0 / 1 -4.4 2 -6.6 -0.07 -8.1
14CHI 26 +0.895 +0.876 +0.018 +23.3 0 / 0 +0.0 1 -1.2 +0.31 +16.9
15LA 34 -0.327 -0.311 -0.016 -11.1 1 / 0 -3.9 3 -3.3 -0.47 -20.0
16MIA 41 +0.149 +0.139 +0.010 +6.1 1 / 0 -3.6 3 -4.5 +0.03 -1.4
17DET 36 +0.385 +0.372 +0.013 +13.9 2 / 0 -11.3 2 -2.3 +0.37 +17.5
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.