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.

Justin Fields — 2021

Adj EPA / dropback
-0.207
Raw EPA / dropback
-0.213
Dropbacks
304
Turnover EPA
-59.7
WPA
-0.88
WeekOpp DropbacksAdj EPA/dbRaw EPA/dbScheduleTotal adj EPA INT / FLTurnover EPASacksSack EPAWPACPOE
1LA 2 +0.294 +0.199 +0.095 +0.6 0 / 0 +0.0 0 +0.0 +0.01 +24.8
2CIN 15 -0.662 -0.644 -0.019 -9.9 1 / 0 -5.1 2 -3.6 -0.19 -8.3
3CLE 29 -0.763 -0.753 -0.010 -22.1 0 / 0 +0.0 9 -16.7 -0.34 -38.8
4DET 18 +0.037 +0.179 -0.141 +0.7 1 / 0 -3.0 1 -2.6 +0.06 +9.2
5LV 21 +0.168 +0.227 -0.058 +3.5 0 / 0 +0.0 2 -1.6 +0.26 -0.9
6GB 31 -0.115 -0.136 +0.021 -3.6 1 / 0 -2.3 4 -6.5 -0.14 -0.3
7TB 36 -0.659 -0.708 +0.049 -23.7 3 / 2 -21.7 4 -14.6 -0.29 +2.4
8SF 31 +0.110 +0.088 +0.022 +3.4 1 / 0 -2.3 4 -5.3 +0.16 +4.8
9PIT 32 +0.196 +0.140 +0.056 +6.3 1 / 0 -4.8 3 -4.2 +0.28 +6.2
11BAL 13 -0.389 -0.378 -0.011 -5.1 0 / 1 -4.8 2 -6.1 -0.20 -16.8
14GB 35 -0.304 -0.323 +0.019 -10.6 2 / 1 -15.8 2 -6.2 -0.26 -7.3
15MIN 41 -0.057 -0.070 +0.013 -2.3 0 / 0 +0.0 3 -8.5 -0.23 +5.9
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.