luckadjusted

Week 9 2021 · November 7, 2021

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

Texans at Dolphins, Week 9 2021: who deserved to win?

The Dolphins beat the Texans 17–9, 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 19 points of win probability to the Dolphins.

Before kickoff the Dolphins were 62% favorites. The biggest swing (Q1, 10:46 left): the Texans were stopped on 3rd & 1, worth 14 points of win probability to the Dolphins.

Final

Houston Texans 9
Miami Dolphins 17

November 7, 2021 · Hard Rock Stadium · Closing line: Dolphins −4

Luck index +42 Dolphins lucky · −42 Texans

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. Texans win 4, Dolphins win 6.

  1. 1 HOU 30 MIA 12
  2. 2 HOU 27 MIA 16
  3. 3 HOU 20 MIA 13
  4. 4 HOU 19 MIA 16
  5. 5 HOU 27 MIA 29
  6. 6 HOU 10 MIA 15
  7. 7 HOU 16 MIA 23
  8. 8 HOU 6 MIA 17
  9. 9 HOU 7 MIA 22
  10. 10 HOU 3 MIA 28

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

Texans win 42% of them, Dolphins 58%, counting the 4% still level after regulation as half each. The line is what actually happened: Dolphins by 8.

Show as a table
Final margin in the replaysShare of replays
Texans by 17+7.0%
Texans by 9–1612.5%
Texans by 1–819.8%
Level after regulation3.7%
Dolphins by 1–825.9%
Dolphins by 9–1617.2%
Dolphins by 17+13.9%

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 +6.7 points to the Dolphins: the final margin was Dolphins by 8, without the luck Dolphins by 1.3. 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.

  • K. Fairbairn, 31 yds made · 93% expected
  • K. Fairbairn, 40 yds made · 82% expected
  • J. Sanders, 42 yds made · 80% expected
  • K. Fairbairn, 20 yds made · 98% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Texans 8 for 60 yards, Dolphins 2 for 13 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 8:19 Defensive Offside on the Texans (DeMarcus Walker), 5 yards · pre-snap +1% MIA +0.5 pts
Q1 1:59 Offensive Holding on the Texans (Antony Auclair), 10 yards +3% MIA +1.0 pts
Q2 9:00 Unnecessary Roughness on the Texans (Desmond King), 15 yards +5% MIA +1.3 pts
Q2 5:43 Delay of Game on the Texans, 5 yards · pre-snap 0% HOU +0.4 pts
Q2 4:37 Delay of Game on the Texans, 5 yards · pre-snap 0% MIA +0.1 pts
Q2 2:57 Defensive Holding on the Texans (Kamu Grugier-Hill), 5 yards +2% MIA +0.8 pts
Q3 11:02 Offensive Pass Interference on the Texans (Danny Amendola), 10 yards, wiping out the play +12% MIA +4.4 pts
Q3 10:32 Offensive Holding on the Dolphins (Clayton Fejedelem), 8 yards +1% HOU +0.9 pts
Q3 4:29 Defensive Holding on the Texans (Desmond King), 5 yards 0% MIA +0.2 pts
Q4 0:35 Delay of Game on the Dolphins, 5 yards · pre-snap 0% HOU +0.7 pts

Texans penalties, every game · Dolphins penalties, every game · All teams, 2021

When it happened

Dolphins’ chance of winning

As low as 39% 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 Texans were.
#WhenWhat happenedWin probability forNext drive
1 Q1 10:46 The Texans were stopped on 3rd & 13rd & 4th downs · 72% expected +14% MIA HOU: Punt
2 Q1 2:36 The Texans converted 3rd & 113rd & 4th downs · 24% expected +7% HOU HOU: Punt
3 Q2 7:37 The Texans converted 3rd & 73rd & 4th downs · 32% expected +7% HOU HOU: Punt
4 Q2 5:43 The Dolphins fumbled and the Texans recoveredFumble bounces · loose balls are close to 50/50Delay of Game on the Texans, 5 yardsPre-snap flags +9% HOU MIA: Field goal
5 Q3 11:46 The Dolphins were stopped on 3rd & 43rd & 4th downs · 43% expected +6% HOU MIA: Punt
6 Q3 11:02 Offensive Pass Interference on the Texans (Danny Amendola), 10 yards, wiping out the playJudgment calls · 4 flags in 1235 snaps before, position avg 1 per 399 +12% MIA MIA: Punt
7 Q4 11:39 The Texans were stopped on 3rd & 13rd & 4th downs · 64% expected +6% MIA HOU: Field goal
8 Q4 11:35 K. Fairbairn made 20-yard field goalKicks · 98% expected for him +8% MIA HOU: Punt

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.

  • DeVante Parker (MIA WR), out (IR) · 0.7 pts
  • Michael Deiter (MIA C), out (IR) · 0.3 pts
  • John Jenkins (MIA NT), out · 0.1 pts
  • Tua Tagovailoa (MIA QB), out, replaced by j.brissett · 0.1 pts
  • Laremy Tunsil (HOU T), out (IR) · 1.1 pts
  • Marcus Cannon (HOU T), out (IR) · 0.7 pts
  • Justin Britt (HOU C), out (IR) · 0.5 pts
  • Christian Kirksey (HOU LB), out (IR) · 0.4 pts
  • Pharaoh Brown (HOU TE), out · 0.3 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

Texans 34% · Dolphins 66%

Final margin
Dolphins by 8
Luck in points
6.7 for the Dolphins
Luck-adjusted margin
Dolphins by 1.3
Replay with same day's form
Texans 42% · Dolphins 58% 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 9 2021 games · Texans · Dolphins

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