luckadjusted

Week 2 2021 · September 20, 2021

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

Lions at Packers, Week 2 2021: who deserved to win?

The Packers beat the Lions 35–17, and it was no fluke: replayed with the way both teams actually played, the Packers win 9 of 10.

Before kickoff the Packers were 80% favorites. The biggest swing (Q3, 12:20 left): the Packers converted 3rd & 12, worth 19 points of win probability to the Packers.

Final

Detroit Lions 17
Green Bay Packers 35

September 20, 2021 · Lambeau Field · Closing line: Packers −11.5

Luck index +10 Packers about even · −10 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, Packers win 9.

  1. 1 DET 28 GB 21
  2. 2 DET 21 GB 23
  3. 3 DET 13 GB 19
  4. 4 DET 19 GB 27
  5. 5 DET 35 GB 45
  6. 6 DET 24 GB 37
  7. 7 DET 19 GB 34
  8. 8 DET 12 GB 31
  9. 9 DET 3 GB 28
  10. 10 DET 0 GB 34

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 10% of them, Packers 90%, counting the 2% still level after regulation as half each. The line is what actually happened: Packers by 18.

Show as a table
Final margin in the replaysShare of replays
Lions by 17+0.6%
Lions by 9–162.5%
Lions by 1–85.9%
Level after regulation1.9%
Packers by 1–817.2%
Packers by 9–1621.8%
Packers by 17+50.1%

Where the luck was

Take the luck out

The final margin was Packers by 18. Remove the luck, one kind at a time, and it becomes Packers by 12.7.

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).

When it happened

Packers’ chance of winning

As low as 37% 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 Packers were ahead in it, below while the Lions were.
#WhenWhat happenedWin probability forNext drive
1 Q1 13:43 The Lions converted 3rd & 13rd & 4th downs · 74% expected +13% DET DET: Touchdown
2 Q2 14:16 The Lions were stopped on 3rd & 93rd & 4th downs · 30% expectedIntentional Grounding on the Lions (Jared Goff), 14 yardsJudgment calls · 5 flags in 2341 snaps before, position avg 1 per 711 +11% GB DET: Punt
3 Q3 12:20 The Packers converted 3rd & 123rd & 4th downs · 27% expected +19% GB GB: Touchdown
4 Q3 10:30 The Packers converted 3rd & 63rd & 4th downs · 40% expected +12% GB GB: Touchdown
5 Q3 8:15 The Lions converted 3rd & 13rd & 4th downs · 74% expected +8% DET DET: Turnover on downs
6 Q3 5:57 The Lions were stopped on 4th & 13rd & 4th downs · 74% expected +14% GB DET: Turnover
7 Q3 5:26 The Packers converted 3rd & 143rd & 4th downs · 25% expected +7% GB GB: Touchdown
8 Q3 3:58 The Packers converted 3rd & 73rd & 4th downs · 37% expected +7% GB GB: 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.

  • David Bakhtiari (GB T), out (IR) · 1.4 pts
  • Za'Darius Smith (GB LB), out (IR) · 0.4 pts
  • Lucas Patrick (GB G), out · 0.3 pts
  • Taylor Decker (DET T), out (IR) · 1.1 pts
  • Tyrell Crosby (DET OL), out (IR) · 0.4 pts
  • Jeff Okudah (DET CB), out (IR) · 0.2 pts
  • Kevin Strong (DET DT), 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

Lions 2% · Packers 98%

Final margin
Packers by 18
Luck in points
5.3 for the Packers
Luck-adjusted margin
Packers by 12.7
Replay with same day's form
Lions 10% · Packers 90% 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 2 2021 games · Lions · Packers

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