luckadjusted

Week 16 2024 · December 22, 2024

49ers at Dolphins, Week 16 2024: who deserved to win?

The Dolphins beat the 49ers 29–17, but the 49ers played well enough to win it: they take 7 of 10 replays with the same day's form. Luck ran their way: kicks alone were worth 12 points of win probability to the Dolphins.

Before kickoff the 49ers were 56% favorites. The biggest swing (Q2, 14:22 left): the 49ers converted 3rd & 8, worth 12 points of win probability to the 49ers.

Final

San Francisco 49ers 17
Miami Dolphins 29

December 22, 2024 · Hard Rock Stadium · Closing line: 49ers −2

Luck index +73 Dolphins very lucky · −73 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 7, Dolphins win 3.

  1. 1 SF 38 MIA 13
  2. 2 SF 40 MIA 20
  3. 3 SF 38 MIA 23
  4. 4 SF 27 MIA 16
  5. 5 SF 20 MIA 12
  6. 6 SF 26 MIA 20
  7. 7 SF 37 MIA 34
  8. 8 SF 27 MIA 30
  9. 9 SF 17 MIA 26
  10. 10 SF 7 MIA 24

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 73% of them, Dolphins 27%, counting the 4% still level after regulation as half each. The line is what actually happened: Dolphins by 12.

Show as a table
Final margin in the replaysShare of replays
49ers by 17+24.5%
49ers by 9–1621.9%
49ers by 1–824.2%
Level after regulation3.8%
Dolphins by 1–814.3%
Dolphins by 9–168.0%
Dolphins by 17+3.5%

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.

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 +12.1 points to the Dolphins: the final margin was Dolphins by 12, without the luck 49ers by 0.1. 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. Sanders, 44 yds made · 79% expected
  • J. Sanders, 38 yds made · 89% expected
  • J. Moody, 21 yds made · 98% expected
  • J. Sanders, 54 yds made · 62% expected
  • J. Moody, 41 yds missed · 83% expected
  • J. Sanders, 33 yds made · 94% expected
  • J. Sanders, 48 yds made · 73% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: 49ers 11 for 90 yards, Dolphins 6 for 45 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 9:28 Offensive Holding on the 49ers, 10 yards +2% MIA +0.9 pts
Q1 9:06 False Start on the 49ers (George Kittle), 5 yards · pre-snap +2% MIA +0.3 pts
Q1 1:43 Defensive Too Many Men on Field on the Dolphins, 5 yards · pre-snap +8% SF +2.3 pts
Q2 11:01 Offensive Holding on the Dolphins, 10 yards +2% SF +0.9 pts
Q2 8:49 False Start on the 49ers, 5 yards · pre-snap +2% MIA +0.7 pts
Q2 8:12 False Start on the 49ers (Brayden Willis), 5 yards · pre-snap 0% SF +0.3 pts
Q2 8:03 Offensive Holding on the Dolphins (Patrick McMorris), 10 yards +3% SF +0.9 pts
Q3 15:00 Unnecessary Roughness on the 49ers (Talanoa Hufanga), 15 yards +5% MIA +2.1 pts
Q3 12:09 Offensive Holding on the Dolphins, 10 yards, wiping out the play +9% SF +2.8 pts
Q3 7:58 Illegal Formation on the 49ers, 5 yards · pre-snap +4% MIA +0.9 pts
Q3 6:47 Illegal Formation on the 49ers, 5 yards, wiping out the play · pre-snap +9% MIA +2.0 pts
Q3 1:08 Kickoff Out of Bounds on the Dolphins (Jason Sanders), 0 yards · pre-snap 0% SF 0.0 pts
Q4 11:56 Unnecessary Roughness on the 49ers (Jordan Elliott), 15 yards +6% MIA +1.4 pts
Q4 10:48 Offensive Holding on the Dolphins, 10 yards +8% SF +1.7 pts
Q4 6:45 Illegal Substitution on the 49ers (Isaac Yiadom), 5 yards · pre-snap +4% MIA +0.5 pts
Q4 6:37 Unnecessary Roughness on the 49ers (Deommodore Lenoir), 15 yards +5% MIA +1.9 pts
Q4 6:13 Defensive Offside on the 49ers (Kalia Davis), 5 yards, wiping out the play · pre-snap +3% SF +0.1 pts

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

When it happened

Dolphins’ chance of winning

As low as 45% 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 Dolphins were ahead in it, below while the 49ers were.
#WhenWhat happenedWin probability forNext drive
1 Q1 1:43 Defensive Too Many Men on Field on the Dolphins, 5 yardsPre-snap flags +8% SF SF: Touchdown
2 Q1 0:58 The 49ers converted 3rd & 103rd & 4th downs · 28% expected +7% SF SF: Touchdown
3 Q2 14:22 The 49ers converted 3rd & 83rd & 4th downs · 32% expected +12% SF SF: Touchdown
4 Q3 12:09 Offensive Holding on the Dolphins, 10 yards, wiping out the playJudgment calls +9% SF SF: Missed field goal
5 Q3 6:47 Illegal Formation on the 49ers, 5 yards, wiping out the playPre-snap flags +9% MIA MIA: Field goal
6 Q3 5:56 J. Moody missed 41-yard field goalKicks · 83% expected for him +7% MIA SF: Touchdown
7 Q4 10:48 Offensive Holding on the Dolphins, 10 yardsJudgment calls +8% SF SF: Punt
8 Q4 2:00 The 49ers threw an interception-worthy pass, and it was pickedInterceptions · 50% expected to stay out of the defense's hands +9% MIA SF: Turnover on downs

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.

  • Jaylen Waddle (MIA WR), out · 1.2 pts
  • Austin Jackson (MIA T), out (IR) · 0.6 pts
  • Trent Williams (SF T), out · 1.2 pts
  • Christian McCaffrey (SF RB), out (IR) · 0.7 pts
  • De'Vondre Campbell (SF LB), out (IR) · 0.5 pts
  • Mitch Wishnowsky (SF P), 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 50% · Dolphins 50%

Final margin
Dolphins by 12
Luck in points
12.1 for the Dolphins
Luck-adjusted margin
49ers by 0.1
Replay with same day's form
49ers 73% · Dolphins 27% 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 16 2024 games · 49ers · Dolphins

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