luckadjusted

Week 18 2021 · January 9, 2022

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

Packers at Lions, Week 18 2021: who deserved to win?

The Lions beat the Packers 37–30, but it was a coin flip: replayed with the way both teams played, the Lions win 5 of 10.

Before kickoff the Packers were 62% favorites. The biggest swing (Q4, 2:31 left): the Lions converted 3rd & 5, worth 13 points of win probability to the Lions.

Final

Green Bay Packers 30
Detroit Lions 37

January 9, 2022 · Ford Field · Closing line: Packers −4

Luck index +47 Lions lucky · −47 Packers

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. Packers win 5, Lions win 5.

  1. 1 GB 37 DET 13
  2. 2 GB 33 DET 16
  3. 3 GB 32 DET 22
  4. 4 GB 26 DET 20
  5. 5 GB 30 DET 27
  6. 6 GB 24 DET 27
  7. 7 GB 14 DET 20
  8. 8 GB 31 DET 41
  9. 9 GB 19 DET 34
  10. 10 GB 16 DET 39

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

Packers win 47% of them, Lions 53%, counting the 5% still level after regulation as half each. The line is what actually happened: Lions by 7.

Show as a table
Final margin in the replaysShare of replays
Packers by 17+12.4%
Packers by 9–1613.3%
Packers by 1–820.1%
Level after regulation4.9%
Lions by 1–821.8%
Lions by 9–1614.8%
Lions by 17+12.7%

Where the luck was

Take the luck out

The final margin was Lions by 7. Remove the luck, one kind at a time, and it becomes Lions by 9.2.

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.

  • R. Patterson, 34 yds made · 95% expected
  • M. Crosby, 36 yds made · 93% expected
  • R. Patterson, 36 yds made · 93% expected
  • R. Patterson, 27 yds made · 98% expected
  • Extra point missed · 95% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Lions’ chance of winning

As low as 28% 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 Lions were ahead in it, below while the Packers were.
#WhenWhat happenedWin probability forNext drive
1 Q1 4:34 The Lions were stopped on 4th & 133rd & 4th downs · 23% expected +8% GB DET: Touchdown
2 Q2 7:03 The Lions converted 4th & 23rd & 4th downs · 52% expected +7% DET DET: Touchdown
3 Q2 2:34 The Packers missed an extra pointKicks · extra points are made about 94% of the time +8% DET GB: End of half
4 Q2 0:42 The Lions converted 4th & 13rd & 4th downs · 73% expected +7% DET DET: Field goal
5 Q3 13:50 The Packers fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +8% GB GB: Turnover
6 Q3 13:04 The Packers were stopped on 3rd & 113rd & 4th downs · 29% expectedThe Packers fumbled and the Lions recoveredFumble bounces · loose balls are close to 50/50 +10% DET GB: Field goal
7 Q4 14:12 The Packers’ two-point try failed3rd & 4th downs · 47% expected +7% DET GB: Touchdown
8 Q4 2:31 The Lions converted 3rd & 53rd & 4th downs · 42% expected +13% DET DET: 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.

  • Penei Sewell (DET T), out · 1.6 pts
  • T.J. Hockenson (DET TE), out (IR) · 1.0 pts
  • Jerry Jacobs (DET CB), out (IR) · 0.6 pts
  • Trinity Benson (DET WR), out · 0.5 pts
  • Amani Oruwariye (DET CB), out (IR) · 0.4 pts
  • Alex Anzalone (DET LB), out (IR) · 0.3 pts
  • Austin Bryant (DET LB), out (IR) · 0.1 pts
  • Billy Turner (GB T), out (IR) · 0.6 pts
  • Randall Cobb (GB WR), out (IR) · 0.6 pts
  • Elgton Jenkins (GB G), out (IR) · 0.5 pts
  • De'Vondre Campbell (GB LB), out · 0.5 pts
  • Kingsley Keke (GB DE), 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

Packers 4% · Lions 96%

Final margin
Lions by 7
Luck in points
2.1 for the Packers
Luck-adjusted margin
Lions by 9.1
Replay with same day's form
Packers 47% · Lions 53% 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 18 2021 games · Packers · Lions

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