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.

Bryce Perkins — 2022

Adj EPA / dropback
-0.468
Raw EPA / dropback
-0.480
Dropbacks
39
Turnover EPA
-10.9
WPA
-0.37
WeekOpp DropbacksAdj EPA/dbRaw EPA/dbScheduleTotal adj EPA INT / FLTurnover EPASacksSack EPAWPACPOE
10ARI 1 -1.142 -1.120 -0.022 -1.1 0 / 0 +0.0 0 +0.0 -0.04 +9.9
11NO 12 -0.302 -0.376 +0.074 -3.6 0 / 0 +0.0 3 -3.2 -0.12 -17.3
12KC 26 -0.519 -0.504 -0.015 -13.5 2 / 0 -10.9 3 -4.8 -0.20 -10.6
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.