luckadjusted

Super Bowl 2023 · February 11, 2024

49ers vs Chiefs, Super Bowl 2023: who deserved to win?

The Chiefs stole one. They beat the 49ers 25–22, but replayed with the way both teams actually played, the 49ers win 8 of 10. Luck ran their way: kicks alone were worth 43 points of win probability to the Chiefs.

Before kickoff the 49ers were 54% favorites. The game turned on a luck play (QOT, 7:25 left): J. Moody made 27-yard field goal, worth 53 points of win probability to the Chiefs.

Final (OT)

San Francisco 49ers 22
Kansas City Chiefs 25

February 11, 2024 · Allegiant Stadium · Closing line: 49ers −1.5

Luck index +84 Chiefs very lucky · −84 49ers

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. 49ers win 8, Chiefs win 2.

  1. 1 SF 65 KC 33
  2. 2 SF 44 KC 19
  3. 3 SF 33 KC 13
  4. 4 SF 26 KC 10
  5. 5 SF 51 KC 38
  6. 6 SF 35 KC 26
  7. 7 SF 37 KC 31
  8. 8 SF 33 KC 31
  9. 9 SF 13 KC 16
  10. 10 SF 14 KC 27

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

49ers win 84% of them, Chiefs 16%, counting the 2% still level after regulation as half each. The line is what actually happened: Chiefs by 3.

Show as a table
Final margin in the replaysShare of replays
49ers by 17+42.8%
49ers by 9–1621.1%
49ers by 1–819.0%
Level after regulation1.6%
Chiefs by 1–89.3%
Chiefs by 9–164.3%
Chiefs by 17+1.9%

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 +5.1 points to the Chiefs: the final margin was Chiefs by 3, without the luck 49ers by 2.1. 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.

  • J. Moody, 55 yds made · 65% expected
  • H. Butker, 28 yds made · 99% expected
  • H. Butker, 57 yds made · 69% expected
  • H. Butker, 24 yds made · 100% expected
  • J. Moody, 53 yds made · 69% expected
  • H. Butker, 29 yds made · 99% expected
  • J. Moody, 27 yds made · 98% expected
  • Extra point missed · 95% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: 49ers 6 for 40 yards, Chiefs 6 for 55 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 8:58 False Start on the 49ers, 5 yards · pre-snap +1% KC +0.5 pts
Q1 8:41 Offensive Holding on the 49ers, 10 yards, wiping out the play +7% KC +2.3 pts
Q1 6:42 False Start on the 49ers (Dee Winters), 5 yards · pre-snap 0% KC +0.4 pts
Q1 3:53 Defensive Offside on the Chiefs, 5 yards, wiping out the play · pre-snap +1% KC +0.1 pts
Q2 11:59 Horse Collar Tackle on the Chiefs (Nick Bolton), 15 yards +4% SF +2.4 pts
Q2 9:16 Intentional Grounding on the Chiefs (Patrick Mahomes), 10 yards +2% SF +1.0 pts
Q2 4:58 Unnecessary Roughness on the Chiefs (L'Jarius Sneed), 15 yards +6% SF +1.3 pts
Q2 2:00 False Start on the Chiefs (Mecole Hardman), 5 yards · pre-snap +4% SF +0.9 pts
Q3 13:26 False Start on the 49ers, 5 yards · pre-snap +2% KC +0.7 pts
QOT 14:55 False Start on the 49ers (Brandon Aiyuk), 5 yards · pre-snap +7% KC +0.7 pts
QOT 14:09 Defensive Holding on the Chiefs (Trent McDuffie), 5 yards +20% SF +2.9 pts
QOT 9:49 Offensive Holding on the 49ers (Brayden Willis), 10 yards +8% KC +2.0 pts

49ers penalties, every game · Chiefs penalties, every game · All teams, 2023

When it happened

Chiefs’ chance of winning

As low as 1% and as high as 100%. 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 Chiefs were ahead in it, below while the 49ers were.
#WhenWhat happenedWin probability forNext drive
1 Q4 9:22 The Chiefs fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50The Chiefs got away with an interception-worthy throwInterceptions · 51% expected to stay out of the defense's hands +27% KC KC: Field goal
2 Q4 0:16 The Chiefs converted 3rd & 73rd & 4th downs · 36% expected +16% KC KC: Field goal
3 QOT 14:09 Defensive Holding on the Chiefs (Trent McDuffie), 5 yardsJudgment calls · 4 flags in 2098 snaps before, position avg 1 per 216 +20% SF SF: Field goal
4 QOT 7:25 The game turned hereJ. Moody made 27-yard field goalKicks · 98% expected for him +53% KC –
5 QOT 6:29 The Chiefs were stopped on 3rd & 13rd & 4th downs · 76% expected +16% SF KC: Touchdown
6 QOT 6:05 The Chiefs converted 4th & 13rd & 4th downs · 75% expected +21% KC KC: Touchdown
7 QOT 4:10 The Chiefs converted 3rd & 63rd & 4th downs · 39% expected +19% KC KC: Touchdown
8 QOT 2:07 The Chiefs converted 3rd & 13rd & 4th downs · 76% expected +19% KC KC: 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.

  • Joe Thuney (KC G), out (IR) · 0.7 pts
  • Charles Omenihu (KC DE), out (IR) · 0.2 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

49ers 64% · Chiefs 36%

Final margin
Chiefs by 3
Luck in points
5.1 for the Chiefs
Luck-adjusted margin
49ers by 2.1
Replay with same day's form
49ers 84% · Chiefs 16% 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 Super Bowl 2023 games · 49ers · Chiefs