luckadjusted

Week 12 2020 · November 29, 2020

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

Chargers at Bills, Week 12 2020: who deserved to win?

The Bills beat the Chargers 27–17, and it was no fluke: replayed with the way both teams actually played, the Bills win 9 of 10. The Chargers had the bounces: fumble bounces alone were worth 16 points of win probability to the Chargers.

Before kickoff the Bills were 63% favorites. The biggest swing (Q4, 10:52 left): the Chargers were stopped on 3rd & 1, worth 11 points of win probability to the Bills.

Final

Los Angeles Chargers 17
Buffalo Bills 27

November 29, 2020 · New Era Field · Closing line: Bills −4.5

Luck index +9 Bills about even · −9 Chargers

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. Chargers win 1, Bills win 9.

  1. 1 LAC 25 BUF 17
  2. 2 LAC 34 BUF 37
  3. 3 LAC 25 BUF 30
  4. 4 LAC 20 BUF 28
  5. 5 LAC 21 BUF 32
  6. 6 LAC 16 BUF 30
  7. 7 LAC 27 BUF 45
  8. 8 LAC 24 BUF 46
  9. 9 LAC 10 BUF 37
  10. 10 LAC 16 BUF 52

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

Chargers win 9% of them, Bills 91%, counting the 1% still level after regulation as half each. The line is what actually happened: Bills by 10.

Show as a table
Final margin in the replaysShare of replays
Chargers by 17+0.6%
Chargers by 9–162.3%
Chargers by 1–86.1%
Level after regulation0.5%
Bills by 1–815.1%
Bills by 9–1620.2%
Bills by 17+55.1%

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 +2.0 points to the Bills: the final margin was Bills by 10, without the luck Bills by 8. Luck shares are the fitted ones (how much of each kind is luck).

The kicks

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

  • T. Bass, 45 yds made · 79% expected
  • M. Badgley, 27 yds made · 97% expected
  • T. Bass, 43 yds made · 82% expected
  • Extra point missed · 93% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Chargers 5 for 91 yards, Bills 9 for 85 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 15:00 Illegal Formation on the Bills (Tyler Matakevich), 5 yards · pre-snap +1% LAC +0.5 pts
Q1 13:15 Defensive Pass Interference on the Chargers (Rayshawn Jenkins), 47 yards +7% BUF +3.4 pts
Q2 12:10 Roughing the Passer on the Chargers (Jerry Tillery), 15 yards +2% BUF +0.7 pts
Q2 6:07 Unnecessary Roughness on the Chargers (Denzel Perryman), 15 yards +2% BUF +1.4 pts
Q2 3:03 False Start on the Bills, 5 yards · pre-snap +1% LAC +0.4 pts
Q3 9:39 Face Mask on the Chargers (Jerry Tillery), 4 yards +1% BUF +0.6 pts
Q3 9:08 Unsportsmanlike Conduct on the Bills (Josh Allen), 15 yards +1% LAC +1.1 pts
Q3 1:12 Unnecessary Roughness on the Bills (Jordan Poyer), 15 yards +4% LAC +1.9 pts
Q4 12:06 Roughing the Passer on the Bills (Ed Oliver), 15 yards +9% LAC +2.0 pts
Q4 11:58 Neutral Zone Infraction on the Bills (Ed Oliver), 5 yards · pre-snap +1% LAC +0.4 pts
Q4 5:17 Unsportsmanlike Conduct on the Bills (Zack Moss), 15 yards +4% LAC +1.5 pts
Q4 3:45 Offensive Holding on the Bills, 10 yards, wiping out the play +4% LAC +2.1 pts
Q4 1:14 Offensive Pass Interference on the Chargers (Jalen Guyton), 10 yards, wiping out the play +7% BUF +4.3 pts
Q4 0:08 Roughing the Passer on the Bills (Quinton Jefferson), 0 yards 0% LAC +0.1 pts

Chargers penalties, every game · Bills penalties, every game · All teams, 2020

When it happened

Bills’ chance of winning

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 Chargers were.
#WhenWhat happenedWin probability forNext drive
1 Q1 13:15 Defensive Pass Interference on the Chargers (Rayshawn Jenkins), 47 yardsJudgment calls · 2 flags in 1705 snaps before, position avg 1 per 510 +7% BUF BUF: Touchdown
2 Q2 12:51 The Bills converted 3rd & 83rd & 4th downs · 32% expected +6% BUF BUF: Touchdown
3 Q3 4:55 The Chargers converted 4th & 13rd & 4th downs · 67% expected +7% LAC LAC: Touchdown
4 Q4 15:00 The Chargers were stopped on 4th & 13rd & 4th downs · 74% expected +8% BUF LAC: Field goal
5 Q4 12:06 Roughing the Passer on the Bills (Ed Oliver), 15 yardsJudgment calls · 5 flags in 994 snaps before, position avg 1 per 262 +9% LAC LAC: Field goal
6 Q4 10:52 The Chargers were stopped on 3rd & 13rd & 4th downs · 67% expected +11% BUF LAC: Field goal
7 Q4 5:23 The Chargers were stopped on 3rd & 63rd & 4th downs · 37% expected +7% BUF LAC: End of game
8 Q4 1:14 Offensive Pass Interference on the Chargers (Jalen Guyton), 10 yards, wiping out the playJudgment calls · 2 flags in 633 snaps before, position avg 1 per 385 +7% BUF –

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.

  • John Brown (BUF WR), out (IR) · 0.6 pts
  • Cody Ford (BUF T), out (IR) · 0.6 pts
  • Matt Milano (BUF LB), out (IR) · 0.3 pts
  • Cameron Lewis (BUF DB), out (IR) · 0.3 pts
  • Tyler Kroft (BUF TE), out · 0.2 pts
  • Casey Hayward (LAC CB), out · 0.9 pts
  • Melvin Ingram (LAC DE), out (IR) · 0.8 pts
  • Casey Hayward (LAC DB), out · 0.7 pts
  • Kyzir White (LAC LB), out (IR) · 0.4 pts
  • Ryan Groy (LAC G), out (IR) · 0.3 pts
  • Kalen Ballage (LAC RB), out · 0.1 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

Chargers 11% · Bills 89%

Final margin
Bills by 10
Luck in points
2.0 for the Bills
Luck-adjusted margin
Bills by 8.0
Replay with same day's form
Chargers 9% · Bills 91% 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 2020 games · Chargers · Bills

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