luckadjusted

Week 1 2023 · September 10, 2023

Dolphins at Chargers, Week 1 2023: who deserved to win?

The Dolphins beat the Chargers 36–34, but it was a coin flip: replayed with the way both teams played, the Dolphins win 6 of 10. Luck ran their way: judgment calls alone were worth 14 points of win probability to the Dolphins.

Before kickoff the Chargers were 59% favorites. The biggest swing (Q4, 1:01 left): the Chargers were stopped on 4th & 12, worth 24 points of win probability to the Dolphins.

Final

Miami Dolphins 36
Los Angeles Chargers 34

September 10, 2023 · SoFi Stadium · Closing line: Chargers −3

Luck index +42 Dolphins lucky · −42 Chargers

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. Dolphins win 6, Chargers win 4.

  1. 1 MIA 45 LAC 17
  2. 2 MIA 38 LAC 20
  3. 3 MIA 27 LAC 14
  4. 4 MIA 33 LAC 24
  5. 5 MIA 37 LAC 32
  6. 6 MIA 33 LAC 31
  7. 7 MIA 19 LAC 22
  8. 8 MIA 28 LAC 35
  9. 9 MIA 24 LAC 36
  10. 10 MIA 20 LAC 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

Dolphins win 58% of them, Chargers 42%, counting the 3% still level after regulation as half each. The line is what actually happened: Dolphins by 2.

Show as a table
Final margin in the replaysShare of replays
Dolphins by 17+15.9%
Dolphins by 9–1615.3%
Dolphins by 1–825.4%
Level after regulation2.7%
Chargers by 1–820.1%
Chargers by 9–1612.3%
Chargers by 17+8.2%

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 +0.1 points to the Dolphins: the final margin was Dolphins by 2, without the luck Dolphins by 1.9. 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, 23 yds made · 99% expected
  • C. Dicker, 50 yds made · 75% expected
  • J. Sanders, 41 yds made · 87% expected
  • J. Sanders, 45 yds made · 81% expected
  • C. Dicker, 25 yds made · 99% expected
  • Extra point missed · 95% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Dolphins 6 for 38 yards, Chargers 6 for 70 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 15:00 Defensive Offside on the Chargers (Joey Bosa), 5 yards · pre-snap 0% MIA +0.4 pts
Q1 2:31 Offensive Holding on the Dolphins, 10 yards +3% LAC +0.9 pts
Q1 2:10 Face Mask on the Chargers (Joey Bosa), 14 yards +4% MIA +0.9 pts
Q2 15:00 False Start on the Chargers, 5 yards · pre-snap +4% MIA +0.9 pts
Q2 4:21 False Start on the Dolphins, 5 yards · pre-snap +4% LAC +0.7 pts
Q2 0:02 Defensive Pass Interference on the Chargers, 30 yards +13% MIA +2.0 pts
Q3 10:04 Defensive Pass Interference on the Dolphins (Xavien Howard), 13 yards +4% LAC +1.2 pts
Q3 9:24 Defensive Pass Interference on the Dolphins (Xavien Howard), 5 yards +4% LAC +1.1 pts
Q3 9:20 Defensive Too Many Men on Field on the Dolphins, 0 yards · pre-snap 0% LAC 0.0 pts
Q4 7:23 Illegal Shift on the Chargers, 5 yards · pre-snap +2% MIA +0.6 pts
Q4 5:15 Illegal Contact on the Dolphins (Xavien Howard), 5 yards +1% LAC +0.2 pts
Q4 1:38 Intentional Grounding on the Chargers (Justin Herbert), 11 yards +6% MIA +1.8 pts

Dolphins penalties, every game · Chargers penalties, every game · All teams, 2023

When it happened

Chargers’ chance of winning

As low as 0% and as high as 84%. 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 Chargers were ahead in it, below while the Dolphins were.
#WhenWhat happenedWin probability forNext drive
1 Q1 12:11 The Dolphins fumbled and the Chargers recoveredFumble bounces · loose balls are close to 50/50 +11% LAC MIA: Touchdown
2 Q2 0:02 Defensive Pass Interference on the Chargers, 30 yardsJudgment calls +13% MIA MIA: Field goal
3 Q3 4:39 The Dolphins were stopped on 3rd & 123rd & 4th downs · 24% expectedThe Dolphins threw an interception-worthy pass, and it was pickedInterceptions · 49% expected to stay out of the defense's hands +17% LAC MIA: Touchdown
4 Q4 13:04 The Dolphins converted 3rd & 153rd & 4th downs · 21% expected +10% MIA MIA: Field goal
5 Q4 6:36 The Chargers converted 3rd & 123rd & 4th downs · 27% expected +11% LAC LAC: Field goal
6 Q4 3:47 The Dolphins converted 3rd & 103rd & 4th downs · 28% expected +24% MIA MIA: Touchdown
7 Q4 1:48 The Dolphins converted 3rd & 43rd & 4th downs · 38% expected +16% MIA MIA: Touchdown
8 Q4 1:01 The Chargers were stopped on 4th & 123rd & 4th downs · 26% expected +24% MIA –

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.

  • Terron Armstead (MIA T), out · 1.0 pts
  • Robert Jones (MIA G), out (IR) · 0.3 pts
  • Keion Crossen (MIA CB), 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

Dolphins 53% · Chargers 47%

Final margin
Dolphins by 2
Luck in points
0.1 for the Dolphins
Luck-adjusted margin
Dolphins by 1.9
Replay with same day's form
Dolphins 58% · Chargers 42% 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 1 2023 games · Dolphins · Chargers

More from Week 1 2023