luckadjusted

Week 15 2021 · December 19, 2021

No FTN charting for this game (drops and interception-worthy throws are not modelled).

Jets at Dolphins, Week 15 2021: who deserved to win?

The Dolphins beat the Jets 31–24 and were the better team on the day: replayed with the same form, they win 7 of 10.

Before kickoff the Dolphins were 78% favorites. The biggest swing (Q4, 7:52 left): Return touchdown by the Jets, worth 28 points of win probability to the Jets.

Final

New York Jets 24
Miami Dolphins 31

December 19, 2021 · Hard Rock Stadium · Closing line: Dolphins −10.5

Luck index +28 Dolphins lucky · −28 Jets

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. Jets win 3, Dolphins win 7.

  1. 1 NYJ 34 MIA 17
  2. 2 NYJ 34 MIA 26
  3. 3 NYJ 16 MIA 13
  4. 4 NYJ 27 MIA 29
  5. 5 NYJ 16 MIA 21
  6. 6 NYJ 17 MIA 25
  7. 7 NYJ 20 MIA 31
  8. 8 NYJ 0 MIA 15
  9. 9 NYJ 13 MIA 33
  10. 10 NYJ 10 MIA 38

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

Jets win 28% of them, Dolphins 72%, counting the 4% still level after regulation as half each. The line is what actually happened: Dolphins by 7.

Show as a table
Final margin in the replaysShare of replays
Jets by 17+3.9%
Jets by 9–168.3%
Jets by 1–814.3%
Level after regulation3.9%
Dolphins by 1–824.0%
Dolphins by 9–1620.6%
Dolphins by 17+25.0%

Where the luck was

Take the luck out

The final margin was Dolphins by 7. Remove the luck, one kind at a time, and it becomes Dolphins by 1.0.

Each row takes one kind of luck out of the margin. Color shows which team it helped. Luck shares are the fitted ones (how much of each component is luck).

The kicks

How likely each kicker was to make that kick (his own record, the distance and the weather), and what happened.

  • E. Pineiro, 27 yds made · 97% expected
  • J. Sanders, 24 yds made · 98% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Dolphins’ chance of winning

As low as 19% 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 Jets were.
#WhenWhat happenedWin probability forNext drive
1 Q2 1:46 The Jets converted 3rd & 153rd & 4th downs · 19% expected +8% NYJ NYJ: Punt
2 Q3 12:11 The Dolphins converted 3rd & 63rd & 4th downs · 36% expected +7% MIA MIA: Touchdown
3 Q3 10:26 The Dolphins converted 3rd & 93rd & 4th downs · 29% expected +9% MIA MIA: Touchdown
4 Q3 6:41 The Jets were stopped on 3rd & 93rd & 4th downs · 28% expected +7% MIA NYJ: Punt
5 Q3 1:12 The Dolphins converted 4th & 13rd & 4th downs · 73% expected +8% MIA MIA: Touchdown
6 Q4 10:27 The Dolphins were stopped on 4th & 13rd & 4th downs · 73% expectedThe Dolphins fumbled and the Jets recoveredFumble bounces · loose balls are close to 50/50 +10% NYJ MIA: Opp touchdown
7 Q4 7:52 Return touchdown by the JetsSpecial teams +28% NYJ NYJ: Opp touchdown
8 Q4 3:43 The Dolphins converted 3rd & 93rd & 4th downs · 29% expected +16% MIA MIA: 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.

  • Jaylen Waddle (MIA WR), out (IR) · 1.2 pts
  • Jevon Holland (MIA FS), out · 0.6 pts
  • Adam Shaheen (MIA TE), out · 0.2 pts
  • Mike White (NYJ QB), out (IR), replaced by z.wilson · 0.9 pts
  • Corey Davis (NYJ WR), out (IR) · 0.8 pts
  • George Fant (NYJ T), out · 0.6 pts
  • Marcus Maye (NYJ FS), out (IR) · 0.4 pts
  • Elijah Moore (NYJ WR), out (IR) · 0.4 pts
  • Shaq Lawson (NYJ DE), out · 0.3 pts
  • Folorunso Fatukasi (NYJ DT), out (IR) · 0.2 pts
  • Shaq Lawson (NYJ LB), out · 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

Jets 19% · Dolphins 81%

Final margin
Dolphins by 7
Luck in points
6.0 for the Dolphins
Luck-adjusted margin
Dolphins by 1.0
Replay with same day's form
Jets 28% · Dolphins 72% 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 (not available for this game); injuries from snap counts and injury reports. No FTN charting for this game (drops and interception-worthy throws are not modelled).

Methodology and validation · All Week 15 2021 games · Jets · Dolphins

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