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.

Case Keenum — 2021

Adj EPA / dropback
-0.101
Raw EPA / dropback
-0.107
Dropbacks
77
Turnover EPA
-11.3
WPA
+0.04
WeekOpp DropbacksAdj EPA/dbRaw EPA/dbScheduleTotal adj EPA INT / FLTurnover EPASacksSack EPAWPACPOE
6ARI 3 -1.294 -1.309 +0.014 -3.9 0 / 0 +0.0 0 +0.0 -0.00 -38.0
7DEN 34 +0.152 +0.140 +0.012 +5.2 0 / 0 +0.0 1 -1.2 +0.11 -1.4
10NE 15 -0.256 -0.289 +0.033 -3.8 0 / 0 +0.0 3 -6.1 -0.00 +4.1
18CIN 25 -0.209 -0.191 -0.018 -5.2 1 / 1 -11.3 1 -8.4 -0.07 +2.9
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.