luckadjusted

Week 11 2021 · November 21, 2021

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

Colts at Bills, Week 11 2021: who deserved to win?

The Colts beat the Bills 41–15, but it was a coin flip: replayed with the way both teams played, the Colts win 6 of 10. Luck ran their way: judgment calls alone were worth 13 points of win probability to the Colts.

Before kickoff the Bills were 71% favorites. The biggest swing (Q1, 4:10 left): the Bills were stopped on 3rd & 18, worth 9 points of win probability to the Colts.

Final

Indianapolis Colts 41
Buffalo Bills 15

November 21, 2021 · New Era Field · Closing line: Bills −7.5

Luck index +41 Colts lucky · −41 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. Colts win 6, Bills win 4.

  1. 1 IND 31 BUF 10
  2. 2 IND 30 BUF 14
  3. 3 IND 21 BUF 10
  4. 4 IND 30 BUF 20
  5. 5 IND 20 BUF 14
  6. 6 IND 30 BUF 28
  7. 7 IND 14 BUF 16
  8. 8 IND 20 BUF 24
  9. 9 IND 23 BUF 34
  10. 10 IND 13 BUF 31

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

Colts win 59% of them, Bills 41%, counting the 3% still level after regulation as half each. The line is what actually happened: Colts by 26.

Show as a table
Final margin in the replaysShare of replays
Colts by 17+12.9%
Colts by 9–1616.6%
Colts by 1–828.4%
Level after regulation2.6%
Bills by 1–820.5%
Bills by 9–1612.6%
Bills by 17+6.4%

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 +15.7 points to the Colts: the final margin was Colts by 26, without the luck Colts by 10.3. 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.

  • M. Badgley, 36 yds made · 89% expected
  • T. Bass, 57 yds missed · 58% expected
  • T. Bass, 49 yds missed · 71% expected
  • M. Badgley, 35 yds made · 90% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Colts 3 for 30 yards, Bills 7 for 56 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 4:38 False Start on the Bills, 5 yards · pre-snap +4% IND +0.8 pts
Q1 4:17 Offensive Holding on the Bills, 10 yards +3% IND +1.5 pts
Q2 9:55 Roughing the Passer on the Bills, 15 yards +7% IND +2.1 pts
Q3 14:19 Delay of Game on the Colts, 5 yards · pre-snap +1% BUF +0.8 pts
Q3 13:36 Unnecessary Roughness on the Bills (Jordan Poyer), 15 yards +1% IND +1.7 pts
Q3 12:21 Defensive Holding on the Bills (Taron Johnson), 5 yards, wiping out the play +3% IND +3.4 pts
Q3 11:51 Offensive Holding on the Colts, 10 yards 0% BUF +1.1 pts
Q3 10:42 Unnecessary Roughness on the Colts, 15 yards +2% BUF +1.8 pts
Q3 1:35 Roughing the Passer on the Bills, 1 yard 0% IND +0.5 pts
Q4 6:17 False Start on the Bills (Dawson Knox), 5 yards · pre-snap 0% IND +0.6 pts

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

When it happened

Bills’ chance of winning

As low as 0% and as high as 57%. 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 Colts were.
#WhenWhat happenedWin probability forNext drive
1 Q1 4:38 False Start on the Bills, 5 yardsPre-snap flags +4% IND IND: Touchdown
2 Q1 4:17 Offensive Holding on the Bills, 10 yardsJudgment calls +3% IND IND: Touchdown
3 Q1 4:10 The Bills were stopped on 3rd & 183rd & 4th downs · 21% expected +9% IND BUF: Touchdown
4 Q2 9:55 Roughing the Passer on the Bills, 15 yardsJudgment calls +7% IND IND: Field goal
5 Q2 6:46 The Colts fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +4% IND IND: Field goal
6 Q2 6:01 The Colts converted 3rd & 103rd & 4th downs · 29% expected +6% IND IND: Field goal
7 Q2 2:12 The Bills fumbled and the Colts recoveredFumble bounces · loose balls are close to 50/50 +6% IND BUF: Missed field goal
8 Q2 0:29 The Bills fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +3% BUF BUF: Missed field goal

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.

  • Spencer Brown (BUF T), out (IR) · 1.2 pts
  • Tremaine Edmunds (BUF LB), out · 0.6 pts
  • Star Lotulelei (BUF DT), out (IR) · 0.4 pts
  • Jon Feliciano (BUF G), out (IR) · 0.3 pts
  • Julian Blackmon (IND FS), out (IR) · 0.4 pts
  • Khari Willis (IND SS), out (IR) · 0.4 pts
  • Rodrigo Blankenship (IND K), out (IR) · 0.3 pts
  • Tyquan Lewis (IND DE), out (IR) · 0.3 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

Colts 94% · Bills 6%

Final margin
Colts by 26
Luck in points
15.7 for the Colts
Luck-adjusted margin
Colts by 10.3
Replay with same day's form
Colts 59% · Bills 41% 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 11 2021 games · Colts · Bills

More from Week 11 2021