AFC Championship 2024 · January 26, 2025
Bills at Chiefs, AFC Championship 2024: who deserved to win?
The Chiefs beat the Bills 32–29, and the replays back it up: with the way both teams actually played, the Chiefs win 9 of 10. The Bills had the bounces: fumble bounces alone were worth 35 points of win probability to the Bills.
An off day for the Bills: their defense played far below its usual level. In a fresh game against the Chiefs they would win 41% of the time; with this day’s form, 7%. The numbers
Before kickoff the Chiefs were 54% favorites. The biggest swing (Q4, 2:00 left): D. Kincaid dropped a catchable pass, worth 29 points of win probability to the Chiefs.
Final
 Buffalo Bills | 29 |
|---|---|
 Kansas City Chiefs | 32 |
Replay with same day's form
Luck index +7 Chiefs about even · −7 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. Bills win 1, Chiefs win 9.
- 1 BUF 20 KC 14
- 2 BUF 34 KC 37
- 3 BUF 16 KC 21
- 4 BUF 20 KC 28
- 5 BUF 16 KC 27
- 6 BUF 14 KC 28
- 7 BUF 6 KC 23
- 8 BUF 10 KC 31
- 9 BUF 17 KC 42
- 10 BUF 7 KC 39
Your call
Did the Chiefs earn it, or get lucky?
Three other ways to ask
Each answers a different question, so none of them replaces the replay above.
Before kickoff
The closing betting line, turned into a probability. What everyone knew before the game.
Same teams, fresh 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.
Only coin-flips re-rolled
Every kick, fumble bounce, drop, conversion and judgment call redrawn; everything else fixed. The narrowest view of luck.
An off day for the Bills
Their defense played far below its usual level. In a fresh game against the Chiefs they would win 41% of the time; with this day’s form, 7%.
Same teams, fresh game
Replay with same day's form
34 points apart for the Bills: the gap is how differently this game went from what the two teams usually are.
| Unit | This game | Usual level | Better or worse than usual |
|---|---|---|---|
| Bills offenseEPA per play gained | +0.16 | +0.19 | worse by 0.04 |
| Bills defenseEPA per play allowed | +0.36 | +0.12 | worse by 0.24 |
| Chiefs offenseEPA per play gained | +0.36 | +0.14 | better by 0.22 |
| Chiefs defenseEPA per play allowed | +0.16 | +0.06 | worse by 0.10 |
EPA (expected points added) per play on competitive snaps, turnovers left out because they are valued as luck. Usual level: the team’s earlier games this season plus half of last season, pulled toward the league average. One team’s defense and the other team’s offense are the same snaps, so one game can’t fully say whose day it was; it shows how far this one was from both teams’ norms.
How 4,000 replays ended
Bills win 7% of them, Chiefs 93%, counting the 1% still level after regulation as half each. The line is what actually happened: Chiefs by 3.
Show as a table
| Final margin in the replays | Share of replays |
|---|---|
| Bills by 17+ | 0.4% |
| Bills by 9–16 | 1.6% |
| Bills by 1–8 | 4.5% |
| Level after regulation | 1.5% |
| Chiefs by 1–8 | 16.5% |
| Chiefs by 9–16 | 23.1% |
| Chiefs by 17+ | 52.5% |
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.
The kicks
How likely each kicker was to make that kick (his own record, the distance and the weather), and what happened.
- T. Bass, 53 yds made · 62% expected
- H. Butker, 35 yds made · 93% expected
Penalties: Bills 6 for 48 yards, Chiefs 5 for 21 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 half toward luck; pre-snap fouls, which repeat, don’t count. How calls are valued
| When | Flag | Win probability for |
|---|---|---|
| Q1 8:56 | Illegal Formation on the Bills, 5 yards · pre-snap | +2% KC +1.0 pts |
| Q1 2:28 | Defensive Offside on the Bills (Ed Oliver), 5 yards, wiping out the play · pre-snap | +6% KC +1.8 pts |
| Q2 14:22 | Defensive Holding on the Chiefs (Nick Bolton), 5 yards | +2% BUF +0.5 pts |
| Q2 4:41 | Face Mask on the Bills (Kaiir Elam), 11 yards | +4% KC +1.2 pts |
| Q2 2:00 | Unnecessary Roughness on the Bills (Jordan Phillips), 8 yards | +2% KC +0.4 pts |
| Q2 1:27 | Defensive Pass Interference on the Chiefs (Jaylen Watson), 5 yards | 0% BUF +0.2 pts |
| Q2 0:23 | Defensive Offside on the Chiefs (Justin Reid), 1 yard · pre-snap | 0% BUF +0.1 pts |
| Q3 13:42 | Defensive Pass Interference on the Bills (Kaiir Elam), 4 yards | +3% KC +0.6 pts |
| Q3 2:13 | False Start on the Chiefs, 5 yards · pre-snap | +2% BUF +0.8 pts |
| Q3 1:56 | Illegal Use of Hands on the Chiefs (Charles Omenihu), 5 yards | +3% BUF +0.8 pts |
| Q4 6:11 | Face Mask on the Bills (Matt Milano), 15 yards | +6% KC +1.8 pts |
Bills penalties, every game · Chiefs penalties, every game · All teams, 2024
When it happened
Chiefs’ chance of winning
As low as 37% and as high as 100%. Numbers mark the biggest luck moments, listed below.
| # | When | What happened | Win probability for | Next drive |
|---|---|---|---|---|
| 1 | Q2 10:53 | The Bills converted 3rd & 133rd & 4th downs · 28% expected | +10% BUF | BUF: Touchdown |
| 2 | Q3 0:56 | The Bills fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 | +10% BUF | BUF: Turnover on downs |
| 3 | Q4 15:00 | The Bills converted 4th & 13rd & 4th downs · 79% expectedThe Bills fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 | +11% BUF | BUF: Turnover on downs |
| 4 | Q4 13:01 | The Bills were stopped on 4th & 13rd & 4th downs · 79% expected | +14% KC | BUF: Touchdown |
| 5 | Q4 7:38 | The Bills converted 3rd & 83rd & 4th downs · 36% expected | +9% BUF | BUF: Touchdown |
| 6 | Q4 6:20 | The Bills converted 4th & 43rd & 4th downs · 43% expected | +13% BUF | BUF: Touchdown |
| 7 | Q4 3:42 | The Chiefs were stopped on 3rd & 173rd & 4th downs · 26% expected | +8% BUF | KC: Field goal |
| 8 | Q4 2:00 | D. Kincaid dropped a catchable passDrops · 5 drops on 143 catchable balls before this | +29% KC | – |
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.
- Taylor Rapp (BUF SS), out · 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
Bills 9% · Chiefs 91%
- Final margin
- Chiefs by 3
- Luck in points
- 5.0 for the Bills
- Luck-adjusted margin
- Chiefs by 8.0
- Replay with same day's form
- Bills 7% · Chiefs 93% unchanged: why
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 Conference championships 2024 games · 
Bills · 
Chiefs
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