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.

Colt McCoy — 2021

Adj EPA / dropback
+0.120
Raw EPA / dropback
+0.136
Dropbacks
105
Turnover EPA
-11.7
WPA
+0.44
WeekOpp DropbacksAdj EPA/dbRaw EPA/dbScheduleTotal adj EPA INT / FLTurnover EPASacksSack EPAWPACPOE
9SF 28 +0.503 +0.476 +0.028 +14.1 0 / 0 +0.0 2 -2.0 +0.24 +12.6
10CAR 22 -0.718 -0.702 -0.016 -15.8 1 / 1 -11.7 2 -7.5 -0.24 -12.6
11SEA 46 +0.327 +0.343 -0.016 +15.0 0 / 0 +0.0 2 -2.9 +0.44 +8.5
15DET 9 -0.082 +0.073 -0.155 -0.7 0 / 0 +0.0 0 +0.0 +0.00 -9.9
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.