luckadjusted

Week 11 2024 · November 17, 2024

Chiefs at Bills, Week 11 2024: who deserved to win?

The Bills beat the Chiefs 30–21, but it was a coin flip: replayed with the way both teams played, the Bills win 5 of 10. Luck ran their way: judgment calls alone were worth 18 points of win probability to the Bills.

Before kickoff the Bills were 57% favorites. The biggest swing (Q4, 2:27 left): the Bills converted 4th & 2, worth 13 points of win probability to the Bills.

Final

Kansas City Chiefs 21
Buffalo Bills 30

November 17, 2024 · New Era Field · Closing line: Bills −2.5

Luck index +50 Bills lucky · −50 Chiefs

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. Chiefs win 5, Bills win 5.

  1. 1 KC 26 BUF 6
  2. 2 KC 28 BUF 14
  3. 3 KC 30 BUF 21
  4. 4 KC 16 BUF 11
  5. 5 KC 28 BUF 26
  6. 6 KC 21 BUF 23
  7. 7 KC 27 BUF 31
  8. 8 KC 9 BUF 17
  9. 9 KC 17 BUF 30
  10. 10 KC 0 BUF 21

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

Chiefs win 50% of them, Bills 50%, counting the 7% still level after regulation as half each. The line is what actually happened: Bills by 9.

Show as a table
Final margin in the replaysShare of replays
Chiefs by 17+10.0%
Chiefs by 9–1613.6%
Chiefs by 1–822.9%
Level after regulation7.0%
Bills by 1–823.7%
Bills by 9–1613.6%
Bills by 17+9.3%

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 +7.9 points to the Bills: the final margin was Bills by 9, without the luck Bills by 1.1. 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, 33 yds made · 94% expected
  • Extra point missed · 93% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Chiefs 6 for 57 yards, Bills 3 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 14:23 Unnecessary Roughness on the Bills (A.J. Epenesa), 15 yards +3% KC +1.4 pts
Q1 8:35 Player Out of Bounds on Kick on the Chiefs (Joshua Williams), 5 yards 0% BUF +0.4 pts
Q1 5:28 Delay of Game on the Bills, 5 yards · pre-snap +2% KC +0.3 pts
Q2 14:07 Defensive Holding on the Chiefs (Felix Anudike-Uzomah), 5 yards, wiping out the play +4% BUF +1.1 pts
Q3 12:07 Delay of Game on the Chiefs, 5 yards · pre-snap +2% BUF +1.0 pts
Q3 5:18 Offensive Holding on the Chiefs, 10 yards +7% BUF +1.7 pts
Q3 2:29 Defensive Pass Interference on the Chiefs (Chamarri Conner), 22 yards +8% BUF +3.5 pts
Q4 8:37 Defensive Pass Interference on the Bills (Christian Benford), 4 yards +4% KC +0.7 pts
Q4 1:24 Offensive Holding on the Chiefs, 10 yards, wiping out the play +4% BUF +2.2 pts

Chiefs penalties, every game · Bills penalties, every game · All teams, 2024

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 Chiefs were.
#WhenWhat happenedWin probability forNext drive
1 Q1 12:59 The Bills converted 3rd & 63rd & 4th downs · 38% expected +9% BUF BUF: Touchdown
2 Q1 9:17 The Chiefs were stopped on 3rd & 53rd & 4th downs · 46% expected +6% BUF KC: Punt
3 Q2 7:38 The Bills were stopped on 4th & 33rd & 4th downs · 53% expectedThe Bills threw an interception-worthy pass, and it was pickedInterceptions · 48% expected to stay out of the defense's hands +12% KC BUF: Field goal
4 Q3 12:53 The Chiefs were stopped on 3rd & 13rd & 4th downs · 78% expected +6% BUF KC: Punt
5 Q3 5:18 Offensive Holding on the Chiefs, 10 yardsJudgment calls +7% BUF BUF: Touchdown
6 Q3 2:29 Defensive Pass Interference on the Chiefs (Chamarri Conner), 22 yardsJudgment calls · 1 flag in 1352 snaps before, position avg 1 per 530 +8% BUF BUF: Touchdown
7 Q4 4:34 The Bills converted 3rd & 93rd & 4th downs · 31% expected +8% BUF BUF: Touchdown
8 Q4 2:27 The Bills converted 4th & 23rd & 4th downs · 61% expected +13% 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.

  • Spencer Brown (BUF T), out · 1.2 pts
  • Dalton Kincaid (BUF TE), out · 0.8 pts
  • Keon Coleman (BUF WR), out · 0.5 pts
  • Rashee Rice (KC WR), out (IR) · 0.6 pts
  • Jaylen Watson (KC CB), out (IR) · 0.5 pts
  • Harrison Butker (KC K), out (IR) · 0.5 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

Chiefs 48% · Bills 52%

Final margin
Bills by 9
Luck in points
7.9 for the Bills
Luck-adjusted margin
Bills by 1.1
Replay with same day's form
Chiefs 50% · Bills 50% 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; injuries from snap counts and injury reports.

Methodology and validation · All Week 11 2024 games · Chiefs · Bills

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