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.

Marcus Mariota — 2026 Every split →

Adj EPA / dropback
+0.234
Raw EPA / dropback
+0.210
Dropbacks
54
Turnover EPA
+0.0
WPA
+0.08
WeekOpp DropbacksAdj EPA/dbRaw EPA/dbScheduleTotal adj EPA INT / FLTurnover EPASacksSack EPAWPACPOE
2DAL 16 +0.285 +0.421 -0.136 +4.6 0 / 0 +0.0 0 +0.0 -0.09 +8.0
3SEA 33 +0.223 +0.117 +0.107 +7.4 0 / 0 +0.0 2 -2.1 +0.15 -0.2
4IND 5 +0.138 +0.150 -0.012 +0.7 0 / 0 +0.0 1 -1.4 +0.02 +10.4
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 2026-10-28 11:05 UTC, from nflverse. Write-up: backtests/nfl_game_quality/FINDINGS.md.