luckadjusted

Week 12 2021 · November 25, 2021

No FTN charting for this game (drops and interception-worthy throws are not modelled).

Bills at Saints, Week 12 2021: who deserved to win?

The Bills beat the Saints 31–6, and it was no fluke: replayed with the way both teams actually played, the Bills win 10 of 10.

Before kickoff the Bills were 70% favorites.

Final

Buffalo Bills 31
New Orleans Saints 6

November 25, 2021 · Mercedes-Benz Superdome · Closing line: Bills −7

Luck index +2 Bills about even · −2 Saints

Each team’s own plays from this game, resampled into new drives 4,000 times: with the way both teams actually played, how often does this performance win? How the replay works

Ten replays. Bills win 10, Saints win 0.

  1. 1 BUF 41 NO 3
  2. 2 BUF 40 NO 10
  3. 3 BUF 40 NO 14
  4. 4 BUF 42 NO 19
  5. 5 BUF 31 NO 12
  6. 6 BUF 26 NO 10
  7. 7 BUF 27 NO 14
  8. 8 BUF 23 NO 13
  9. 9 BUF 20 NO 13
  10. 10 BUF 10 NO 7

Three other ways to ask

Each answers a different question, so none of them replaces the replay above.

The closing betting line, turned into a probability. What everyone knew before the game.

The line plus what this game showed, weighted by how much one game can tell. It stays close to the line because one game says little.

Every kick, fumble bounce, drop, conversion and judgment call redrawn; everything else fixed. The narrowest view of luck.

How 4,000 replays ended

Bills win 98% of them, Saints 2%, counting the 1% still level after regulation as half each. The line is what actually happened: Bills by 25.

Show as a table
Final margin in the replaysShare of replays
Bills by 17+75.7%
Bills by 9–1616.4%
Bills by 1–85.5%
Level after regulation0.7%
Saints by 1–81.3%
Saints by 9–160.3%
Saints by 17+0.1%

Where the luck was

What the luck was worth

Every lucky and unlucky play, weighted by the moment it happened: its swing in win probability, added up by kind. A missed kick in a decided game counts for nothing; the same kick at the end of a tie game can be most of a win.

Swings add up across a game, so in one that went back and forth they can pass 100%. On the scoreboard the same luck was worth +7.6 points to the Bills: the final margin was Bills by 25, without the luck Bills by 17.4. Luck shares are the fitted ones (how much of each kind is luck).

Penalties: Bills 4 for 35 yards, Saints 4 for 24 yards

Every accepted flag, in order, and what it did to the helped team’s chance of winning at that moment, including any play it wiped out (points on the scoreboard in grey). A flag in a decided game is worth nothing; one at the turn of a close game can be worth most of a win. Judgment calls count toward luck, pre-snap fouls mostly don’t. How calls are valued

WhenFlagWin probability for
Q1 5:21 False Start on the Saints, 5 yards · pre-snap +1% BUF +0.6 pts
Q2 6:08 Offensive Holding on the Bills, 10 yards +2% NO +1.2 pts
Q2 0:33 Defensive Offside on the Saints (Cameron Jordan), 5 yards · pre-snap 0% BUF +0.4 pts
Q2 0:22 Ineligible Downfield Pass on the Bills, 5 yards, wiping out the play +5% NO +3.2 pts
Q3 10:21 Defensive Pass Interference on the Saints (Marshon Lattimore), 9 yards +1% BUF +0.9 pts
Q3 3:38 Roughing the Passer on the Bills (Ed Oliver), 15 yards 0% NO +1.5 pts
Q3 0:34 False Start on the Saints (Lil'Jordan Humphrey), 5 yards · pre-snap 0% BUF +0.6 pts
Q4 4:45 Delay of Game on the Bills, 5 yards · pre-snap 0% NO +0.5 pts

Bills penalties, every game · Saints penalties, every game · All teams, 2021

When it happened

Saints’ chance of winning

As low as 0% and as high as 55%. Numbers mark the biggest luck moments, listed below.

nflfastR’s in-game win probability. It ignores the betting line, so it starts near even. Shaded above the middle while the Saints were ahead in it, below while the Bills were.
#WhenWhat happenedWin probability forNext drive
1 Q1 4:10 The Saints were stopped on 3rd & 23rd & 4th downs · 58% expected +6% BUF NO: Punt
2 Q1 0:32 The Bills were stopped on 3rd & 133rd & 4th downs · 25% expected +6% NO BUF: Punt
3 Q2 12:51 The Saints were stopped on 4th & 23rd & 4th downs · 57% expected +6% BUF NO: Punt
4 Q2 11:37 The Bills converted 3rd & 23rd & 4th downs · 62% expected +6% BUF BUF: Field goal
5 Q2 4:32 The Bills converted 3rd & 63rd & 4th downs · 38% expected +4% BUF BUF: Turnover
6 Q2 1:51 The Saints were stopped on 4th & 83rd & 4th downs · 29% expected +5% BUF NO: End of half
7 Q2 0:22 Ineligible Downfield Pass on the Bills, 5 yards, wiping out the playJudgment calls +5% NO NO: End of half
8 Q3 13:51 The Bills converted 3rd & 73rd & 4th downs · 36% expected +6% BUF BUF: Touchdown

Missing players

Key players (usually on the field for half the snaps or more) who missed this game or part of it, valued by position and quality. The same players are missing in every replay, so this counts as luck in points only.

  • Jameis Winston (NO QB), out (IR), replaced by t.siemian · 4.8 pts
  • Ryan Ramczyk (NO T), out · 1.6 pts
  • Alvin Kamara (NO RB), out · 0.6 pts
  • Adam Trautman (NO TE), out (IR) · 0.4 pts
  • Andrus Peat (NO G), out (IR) · 0.4 pts
  • Marcus Davenport (NO DE), out · 0.4 pts
  • Mark Ingram (NO RB), out · 0.3 pts
  • Spencer Brown (BUF T), out (IR) · 1.2 pts
  • Star Lotulelei (BUF DT), out (IR) · 0.4 pts
  • Jon Feliciano (BUF G), out (IR) · 0.3 pts
  • Zack Moss (BUF RB), out · 0.2 pts

Adjust the assumptions

Disagree with how much of a fumble bounce or a pass interference call is luck? Change it and the coin-flip replay reruns in your browser.

Only coin-flips re-rolled

Bills 100% · Saints 0%

Final margin
Bills by 25
Luck in points
7.6 for the Bills
Luck-adjusted margin
Bills by 17.4
Replay with same day's form
Bills 98% · Saints 2% unchanged: why
How much of each is luck?

0% treats it as skill, 100% as pure luck. The tick is our fit.

What counts

We tested momentum on 19,000 lucky breaks and found none, so it's off by default. Why

Flip a play

Force the other outcome, in this game and in every replay: a made kick becomes a miss, a stop becomes a conversion, a flag goes the other way.

About these numbers

Play-by-play and win probability from nflfastR via nflverse; kicks valued against each kicker’s own record; drops and interception-worthy throws from FTN charting (not available for this game); injuries from snap counts and injury reports. No FTN charting for this game (drops and interception-worthy throws are not modelled).

Methodology and validation · All Week 12 2021 games · Bills · Saints

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