luckadjusted

Week 7 2024 · October 20, 2024

Chiefs at 49ers, Week 7 2024: who deserved to win?

The Chiefs beat the 49ers 28–18 and were the better team on the day: replayed with the same form, they win 6 of 10.

Before kickoff the 49ers were 57% favorites. The biggest swing (Q4, 9:34 left): the 49ers were stopped on 3rd & 5, worth 23 points of win probability to the Chiefs.

Final

Kansas City Chiefs 28
San Francisco 49ers 18

October 20, 2024 · Levi's Stadium · Closing line: 49ers −2.5

Luck index +38 Chiefs lucky · −38 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. Chiefs win 6, 49ers win 4.

  1. 1 KC 39 SF 13
  2. 2 KC 34 SF 16
  3. 3 KC 37 SF 24
  4. 4 KC 27 SF 17
  5. 5 KC 22 SF 17
  6. 6 KC 21 SF 19
  7. 7 KC 26 SF 29
  8. 8 KC 21 SF 27
  9. 9 KC 20 SF 33
  10. 10 KC 20 SF 41

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 62% of them, 49ers 38%, counting the 3% still level after regulation as half each. The line is what actually happened: Chiefs by 10.

Show as a table
Final margin in the replaysShare of replays
Chiefs by 17+16.7%
Chiefs by 9–1616.7%
Chiefs by 1–825.4%
Level after regulation3.1%
49ers by 1–818.6%
49ers by 9–1612.1%
49ers by 17+7.3%

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 +5.9 points to the Chiefs: the final margin was Chiefs by 10, without the luck Chiefs by 4.1. 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.

  • A. Carlson, 55 yds made · 63% expected
  • A. Carlson, 24 yds made · 98% expected
  • Extra point missed · 93% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Chiefs 4 for 48 yards, 49ers 6 for 40 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 Offensive Holding on the 49ers, 10 yards, wiping out the play +3% KC +1.9 pts
Q1 2:05 Defensive Pass Interference on the Chiefs (Justin Reid), 18 yards +3% SF +1.5 pts
Q2 13:45 Defensive Offside on the 49ers (Sam Okuayinonu), 6 yards · pre-snap +1% KC +0.9 pts
Q2 12:46 Defensive Offside on the 49ers (Kevin Givens), 4 yards · pre-snap 0% SF +0.3 pts
Q2 11:52 Defensive Too Many Men on Field on the 49ers, 0 yards · pre-snap 0% KC 0.0 pts
Q2 6:45 Offensive Holding on the 49ers, 10 yards, wiping out the play +4% KC +1.7 pts
Q2 1:55 Offensive Holding on the 49ers (George Odum), 10 yards +2% KC +1.0 pts
Q2 1:39 Defensive Pass Interference on the Chiefs (Trent McDuffie), 10 yards +1% SF +0.5 pts
Q4 12:49 Defensive Holding on the Chiefs (Nazeeh Johnson), 5 yards, wiping out the play +1% SF +0.9 pts
Q4 2:00 Face Mask on the Chiefs (Joshua Williams), 15 yards 0% SF +1.8 pts

Chiefs penalties, every game · 49ers penalties, every game · All teams, 2024

When it happened

49ers’ chance of winning

As low as 0% and as high as 60%. 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 49ers were ahead in it, below while the Chiefs were.
#WhenWhat happenedWin probability forNext drive
1 Q1 11:07 The Chiefs converted 3rd & 63rd & 4th downs · 39% expected +6% KC KC: Turnover on downs
2 Q1 2:00 The 49ers got away with an interception-worthy throwInterceptions · 48% expected to stay out of the defense's hands +6% SF SF: Field goal
3 Q2 10:42 The 49ers were stopped on 3rd & 23rd & 4th downs · 61% expectedB. Aiyuk dropped a catchable passDrops · 10 drops on 209 catchable balls before this +8% KC SF: Punt
4 Q2 1:24 The 49ers converted 3rd & 43rd & 4th downs · 46% expected +6% SF SF: Field goal
5 Q3 14:07 The Chiefs were stopped on 3rd & 83rd & 4th downs · 33% expectedThe Chiefs threw an interception-worthy pass, and it was pickedInterceptions · 53% expected to stay out of the defense's hands +14% SF KC: Punt
6 Q3 6:02 The 49ers were stopped on 3rd & 63rd & 4th downs · 37% expectedThe 49ers threw an interception-worthy pass, and it was pickedInterceptions · 47% expected to stay out of the defense's hands +21% KC SF: Turnover
7 Q4 14:17 The Chiefs converted 4th & 13rd & 4th downs · 68% expected +7% KC KC: Touchdown
8 Q4 9:34 The 49ers were stopped on 3rd & 53rd & 4th downs · 33% expectedThe 49ers threw an interception-worthy pass, and it was pickedInterceptions · 48% expected to stay out of the defense's hands +23% KC SF: 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.

  • Christian McCaffrey (SF RB), out (IR) · 0.7 pts
  • Javon Hargrave (SF DT), out (IR) · 0.4 pts
  • Talanoa Hufanga (SF SS), out (IR) · 0.4 pts
  • Jauan Jennings (SF WR), out · 0.3 pts
  • Jake Moody (SF K), out · 0.3 pts
  • Jon Feliciano (SF C), out (IR) · 0.2 pts
  • Dre Greenlaw (SF LB), out (IR) · 0.2 pts
  • Rashee Rice (KC WR), out (IR) · 0.6 pts
  • Michael Danna (KC DE), out · 0.5 pts
  • Isiah Pacheco (KC RB), out (IR) · 0.4 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 86% · 49ers 14%

Final margin
Chiefs by 10
Luck in points
5.9 for the Chiefs
Luck-adjusted margin
Chiefs by 4.1
Replay with same day's form
Chiefs 62% · 49ers 38% 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 7 2024 games · Chiefs · 49ers

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