luckadjusted

Week 17 2021 · January 2, 2022

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

Lions at Seahawks, Week 17 2021: who deserved to win?

The Seahawks beat the Lions 51–29, and it was no fluke: replayed with the way both teams actually played, the Seahawks win 9 of 10.

Before kickoff the Seahawks were 74% favorites. The biggest swing (Q1, 9:44 left): the Lions were stopped on 4th & 1, worth 9 points of win probability to the Seahawks.

Final

Detroit Lions 29
Seattle Seahawks 51

January 2, 2022 · Lumen Field · Closing line: Seahawks −8.5

Luck index +14 Seahawks about even · −14 Lions

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. Lions win 1, Seahawks win 9.

  1. 1 DET 19 SEA 10
  2. 2 DET 31 SEA 33
  3. 3 DET 28 SEA 33
  4. 4 DET 26 SEA 34
  5. 5 DET 23 SEA 35
  6. 6 DET 17 SEA 31
  7. 7 DET 26 SEA 43
  8. 8 DET 10 SEA 31
  9. 9 DET 7 SEA 34
  10. 10 DET 15 SEA 51

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

Lions win 14% of them, Seahawks 86%, counting the 2% still level after regulation as half each. The line is what actually happened: Seahawks by 22.

Show as a table
Final margin in the replaysShare of replays
Lions by 17+1.4%
Lions by 9–163.8%
Lions by 1–87.5%
Level after regulation2.0%
Seahawks by 1–817.6%
Seahawks by 9–1621.0%
Seahawks by 17+46.7%

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 +10.2 points to the Seahawks: the final margin was Seahawks by 22, without the luck Seahawks by 11.8. 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. Myers, 51 yds made · 69% expected
  • R. Patterson, 55 yds missed · 64% expected
  • J. Myers, 36 yds made · 91% expected
  • J. Myers, 42 yds made · 84% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Lions 4 for 30 yards, Seahawks 5 for 31 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 7:09 Defensive Holding on the Lions (Will Harris), 5 yards 0% SEA +0.2 pts
Q2 5:46 Offensive Holding on the Seahawks (Edmond Robinson), 10 yards +1% DET +0.9 pts
Q3 14:00 Defensive Holding on the Seahawks (Al Woods), 5 yards 0% DET +0.9 pts
Q3 10:34 False Start on the Lions, 5 yards · pre-snap 0% SEA +0.9 pts
Q3 10:13 Offensive Holding on the Lions, 10 yards 0% SEA +0.9 pts
Q3 5:50 Offensive Holding on the Lions, 10 yards 0% SEA +1.6 pts
Q3 5:21 Face Mask on the Seahawks (Jordyn Brooks), 6 yards 0% DET +1.1 pts
Q4 14:14 False Start on the Seahawks, 5 yards · pre-snap 0% DET +0.6 pts
Q4 12:36 Defensive Holding on the Seahawks (Ugo Amadi), 5 yards 0% DET +0.2 pts

Lions penalties, every game · Seahawks penalties, every game · All teams, 2021

When it happened

Seahawks’ chance of winning

As low as 40% 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 Seahawks were ahead in it, below while the Lions were.
#WhenWhat happenedWin probability forNext drive
1 Q1 14:06 The Seahawks were stopped on 3rd & 73rd & 4th downs · 35% expected +4% DET SEA: Punt
2 Q1 12:47 The Lions converted 3rd & 53rd & 4th downs · 37% expected +5% DET DET: Turnover on downs
3 Q1 9:44 The Lions were stopped on 4th & 13rd & 4th downs · 70% expected +9% SEA DET: Punt
4 Q1 8:35 The Seahawks converted 3rd & 103rd & 4th downs · 28% expected +7% SEA SEA: Touchdown
5 Q1 1:05 J. Myers made 51-yard field goalKicks · 69% expected for him, 15 of 22 from 45+ before +5% SEA SEA: Touchdown
6 Q2 11:16 The Lions converted 3rd & 103rd & 4th downs · 24% expected +8% DET DET: Touchdown
7 Q2 9:56 The Seahawks converted 3rd & 63rd & 4th downs · 38% expected +4% SEA SEA: Touchdown
8 Q2 6:03 The Seahawks converted 3rd & 83rd & 4th downs · 33% expected +3% SEA SEA: 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.

  • Brandon Shell (SEA T), out · 0.8 pts
  • Jamal Adams (SEA SS), out (IR) · 0.7 pts
  • Damien Lewis (SEA G), out (IR) · 0.5 pts
  • Sidney Jones (SEA CB), out (IR) · 0.4 pts
  • Tre Brown (SEA DB), out (IR) · 0.3 pts
  • Jared Goff (DET QB), out, replaced by t.boyle · 4.6 pts
  • T.J. Hockenson (DET TE), out (IR) · 1.0 pts
  • Jerry Jacobs (DET CB), out (IR) · 0.6 pts
  • Kalif Raymond (DET WR), out (IR) · 0.5 pts
  • Josh Reynolds (DET WR), out (IR) · 0.5 pts
  • Amani Oruwariye (DET CB), out (IR) · 0.4 pts
  • Alex Anzalone (DET LB), out (IR) · 0.3 pts
  • Halapoulivaati Vaitai (DET G), out (IR) · 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

Lions 0% · Seahawks 100%

Final margin
Seahawks by 22
Luck in points
10.2 for the Seahawks
Luck-adjusted margin
Seahawks by 11.8
Replay with same day's form
Lions 14% · Seahawks 86% 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 17 2021 games · Lions · Seahawks

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