Game quality
How well each team played, beyond the score: EPA (expected points added) per play, adjusted for the opponent. A big day against a bad defence counts for less. Season views include playoff games.
Bailey Zappe — 2022 Every split →
Adj EPA / dropback
+0.062
Raw EPA / dropback
+0.078
Dropbacks
98
Turnover EPA
-21.1
WPA
+0.26
| Week | Opp | Dropbacks | Adj EPA/db | Raw EPA/db | Schedule | Total adj EPA | INT / FL | Turnover EPA | Sacks | Sack EPA | WPA | CPOE |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 4 | GB | 18 | -0.251 | -0.264 | +0.013 | -4.5 | 0 / 1 | -4.7 | 3 | -5.6 | -0.28 | +1.1 |
| 5 | DET | 21 | +0.221 | +0.312 | -0.091 | +4.6 | 1 / 0 | -3.8 | 0 | +0.0 | +0.07 | +13.2 |
| 6 | CLE | 36 | +0.277 | +0.234 | +0.043 | +10.0 | 0 / 1 | -4.2 | 2 | -6.0 | +0.31 | +9.8 |
| 7 | CHI | 23 | -0.173 | -0.110 | -0.064 | -4.0 | 2 / 0 | -8.5 | 1 | -2.5 | +0.16 | -4.1 |
How the ratings are built
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 2026-11-07 11:05 UTC, from nflverse. Write-up:
backtests/nfl_game_quality/FINDINGS.md.