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.

Davis Mills — 2021

Adj EPA / dropback
-0.100
Raw EPA / dropback
-0.104
Dropbacks
424
Turnover EPA
-48.9
WPA
-0.54
WeekOpp DropbacksAdj EPA/dbRaw EPA/dbScheduleTotal adj EPA INT / FLTurnover EPASacksSack EPAWPACPOE
2CLE 19 +0.042 +0.024 +0.019 +0.8 1 / 0 -3.4 1 -1.3 -0.08 -16.9
3CAR 31 -0.240 -0.233 -0.007 -7.4 0 / 0 +0.0 4 -7.0 -0.10 +6.1
4BUF 24 -0.905 -0.955 +0.050 -21.7 4 / 0 -16.3 3 -4.8 -0.43 -15.9
5NE 32 +0.613 +0.560 +0.053 +19.6 0 / 0 +0.0 3 -3.8 +0.43 +9.3
6IND 45 -0.196 -0.200 +0.004 -8.8 2 / 0 -9.9 2 -3.2 -0.19 -2.0
7ARI 34 -0.472 -0.482 +0.010 -16.1 0 / 1 -5.9 2 -8.0 -0.16 +0.1
8LA 43 -0.064 -0.160 +0.096 -2.7 1 / 0 -5.2 5 -9.2 -0.29 +8.4
13IND 16 -0.774 -0.767 -0.007 -12.4 0 / 0 +0.0 2 -3.8 -0.01 -25.4
14SEA 50 -0.067 -0.040 -0.027 -3.3 0 / 0 +0.0 2 -2.8 -0.03 -3.5
15JAX 31 -0.022 +0.113 -0.135 -0.7 1 / 0 -3.6 1 -0.8 +0.01 -2.2
16LAC 28 +0.578 +0.572 +0.006 +16.2 0 / 0 +0.0 1 -1.8 +0.46 +7.6
17SF 35 -0.455 -0.458 +0.003 -15.9 1 / 0 -4.5 3 -5.7 -0.38 +1.2
18TEN 36 +0.284 +0.296 -0.013 +10.2 0 / 0 +0.0 2 -3.0 +0.24 +6.8
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.