luckadjusted

Week 13 2021 · December 6, 2021

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

Patriots at Bills, Week 13 2021: who deserved to win?

The Patriots beat the Bills 14–10, but it was a coin flip: replayed with the way both teams played, the Patriots win 5 of 10. Luck ran their way: kicks alone were worth 4.4 points to the Patriots.

Before kickoff the Bills were 59% favorites. The biggest swing (Q4, 2:00 left): the Bills were stopped on 4th & 14, worth 30 points of win probability to the Patriots.

Final

New England Patriots 14
Buffalo Bills 10

December 6, 2021 · New Era Field · Closing line: Bills −3

Luck index +47 Patriots lucky · −47 Bills

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. Patriots win 5, Bills win 5.

  1. 1 NE 29 BUF 7
  2. 2 NE 24 BUF 10
  3. 3 NE 29 BUF 20
  4. 4 NE 19 BUF 14
  5. 5 NE 15 BUF 12
  6. 6 NE 16 BUF 18
  7. 7 NE 24 BUF 28
  8. 8 NE 14 BUF 22
  9. 9 NE 7 BUF 20
  10. 10 NE 17 BUF 35

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

Patriots win 53% of them, Bills 47%, counting the 6% still level after regulation as half each. The line is what actually happened: Patriots by 4.

Show as a table
Final margin in the replaysShare of replays
Patriots by 17+11.2%
Patriots by 9–1615.1%
Patriots by 1–822.4%
Level after regulation6.0%
Bills by 1–822.5%
Bills by 9–1613.3%
Bills by 17+9.5%

Where the luck was

Take the luck out

The final margin was Patriots by 4. Remove the luck, one kind at a time, and it becomes Patriots by 0.4.

Each row takes one kind of luck out of the margin. Color shows which team it helped. Luck shares are the fitted ones (how much of each component is luck).

The kicks

How likely each kicker was to make that kick (his own record, the distance and the weather), and what happened.

  • N. Folk, 41 yds made · 76% expected
  • T. Bass, 35 yds made · 86% expected
  • N. Folk, 34 yds made · 89% expected
  • T. Bass, 33 yds missed · 89% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Bills’ chance of winning

As low as 0% and as high as 71%. 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 Bills were ahead in it, below while the Patriots were.
#WhenWhat happenedWin probability forNext drive
1 Q1 5:28 The Patriots converted 3rd & 53rd & 4th downs · 40% expected +21% NE NE: Touchdown
2 Q3 11:36 Offensive Holding on the Patriots (Jonnu Smith), 10 yards, wiping out the playJudgment calls · 10 flags in 2108 snaps before, position avg 1 per 269 +10% BUF BUF: Field goal
3 Q3 7:50 Unnecessary Roughness on the Patriots, 15 yardsJudgment calls +8% BUF BUF: Field goal
4 Q3 3:09 The Patriots converted 4th & 13rd & 4th downs · 72% expected +7% NE NE: Field goal
5 Q4 13:05 N. Folk made 34-yard field goalKicks · 89% expected for him +12% NE NE: Punt
6 Q4 7:28 T. Bass missed 33-yard field goalKicks · 89% expected for him +14% NE BUF: Turnover on downs
7 Q4 2:11 The Bills were stopped on 3rd & 143rd & 4th downs · 23% expectedFalse Start on the Bills (Dawson Knox), 5 yardsPre-snap flags · 4 flags in 1962 snaps before, position avg 1 per 269 +14% NE BUF: Turnover on downs
8 Q4 2:00 The Bills were stopped on 4th & 143rd & 4th downs · 23% expected +30% NE –

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.

  • Tre'Davious White (BUF CB), out (IR) · 1.2 pts
  • Jon Feliciano (BUF G), out (IR) · 0.3 pts
  • Kyle Dugger (NE FS), out (IR) · 0.4 pts
  • Jonathan Jones (NE CB), out (IR) · 0.4 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

Patriots 53% · Bills 47%

Final margin
Patriots by 4
Luck in points
3.6 for the Patriots
Luck-adjusted margin
Patriots by 0.4
Replay with same day's form
Patriots 53% · Bills 47% 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 13 2021 games · Patriots · Bills

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