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 Herbert — 2024

Adj EPA / dropback
+0.091
Raw EPA / dropback
+0.086
Dropbacks
581
Turnover EPA
-39.8
WPA
+1.54
WeekOpp DropbacksAdj EPA/dbRaw EPA/dbScheduleTotal adj EPA INT / FLTurnover EPASacksSack EPAWPACPOE
1LV 27 -0.175 -0.181 +0.006 -4.7 0 / 0 +0.0 1 -2.4 -0.15 -0.6
2CAR 21 +0.013 +0.068 -0.055 +0.3 1 / 1 -9.0 1 -4.5 +0.03 +7.7
3PIT 20 +0.091 +0.078 +0.013 +1.8 0 / 0 +0.0 2 -3.0 -0.11 +3.4
4KC 29 -0.057 -0.071 +0.013 -1.7 0 / 0 +0.0 2 -2.3 -0.05 -6.5
6DEN 37 +0.239 +0.219 +0.020 +8.8 0 / 0 +0.0 3 -3.9 +0.20 +1.4
7ARI 41 +0.248 +0.316 -0.068 +10.2 0 / 0 +0.0 3 -3.6 +0.26 +4.8
8NO 35 +0.097 +0.061 +0.035 +3.4 0 / 0 +0.0 3 -5.8 -0.04 -3.1
9CLE 33 +0.091 +0.040 +0.051 +3.0 0 / 0 +0.0 6 -6.0 +0.17 +8.3
10TEN 18 +0.522 +0.537 -0.015 +9.4 0 / 0 +0.0 0 +0.0 +0.25 +8.6
11CIN 37 +0.044 +0.062 -0.018 +1.6 0 / 0 +0.0 2 -3.9 +0.13 -11.7
12BAL 40 +0.045 -0.046 +0.091 +1.8 0 / 0 +0.0 4 -5.6 +0.13 -8.0
13ATL 29 -0.218 -0.179 -0.039 -6.3 0 / 0 +0.0 5 -5.7 -0.23 +1.2
14KC 33 +0.266 +0.247 +0.019 +8.8 0 / 0 +0.0 3 -3.9 +0.20 +8.5
15TB 36 -0.356 -0.310 -0.045 -12.8 1 / 0 -3.2 3 -3.8 -0.08 -0.8
16DEN 34 +0.388 +0.362 +0.026 +13.2 1 / 0 -4.1 2 -3.9 +0.48 +7.4
17NE 38 +0.495 +0.517 -0.022 +18.8 0 / 0 +0.0 0 +0.0 +0.40 +7.6
18LV 37 +0.523 +0.498 +0.025 +19.3 0 / 0 +0.0 1 -3.6 +0.33 +10.0
19HOU 36 -0.619 -0.640 +0.022 -22.3 4 / 0 -23.5 4 -6.6 -0.39 -20.7
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.