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.

Jake Fromm — 2021

Adj EPA / dropback
-0.536
Raw EPA / dropback
-0.533
Dropbacks
66
Turnover EPA
-22.0
WPA
-0.72
WeekOpp DropbacksAdj EPA/dbRaw EPA/dbScheduleTotal adj EPA INT / FLTurnover EPASacksSack EPAWPACPOE
15DAL 13 +0.025 -0.048 +0.073 +0.3 0 / 0 +0.0 1 -0.7 -0.01 -5.3
16PHI 19 -0.834 -0.803 -0.032 -15.9 1 / 0 -5.2 2 -4.1 -0.42 -32.5
18WAS 34 -0.584 -0.567 -0.017 -19.8 2 / 1 -16.9 3 -9.1 -0.29 -16.4
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.