luckadjusted

Week 17 2019 · December 29, 2019

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

Packers at Lions, Week 17 2019: who deserved to win?

The Packers beat the Lions 23–20, but it was a coin flip: replayed with the way both teams played, the Packers win 4 of 10. Luck ran their way: injuries alone were worth 3.4 points to the Packers.

The Packers won on an off day: they played far below what the matchup promised. In a fresh game against the Lions they would win 83% of the time; with this day’s form, 43%. The numbers

Before kickoff the Packers were 84% favorites. The biggest swing (Q4, 5:24 left): the Packers converted 3rd & 10, worth 23 points of win probability to the Packers.

Final

Green Bay Packers 23
Detroit Lions 20

December 29, 2019 · Ford Field · Closing line: Packers −13.5

Luck index +57 Packers lucky · −57 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. Packers win 4, Lions win 6.

  1. 1 GB 33 DET 13
  2. 2 GB 20 DET 10
  3. 3 GB 30 DET 25
  4. 4 GB 37 DET 35
  5. 5 GB 17 DET 20
  6. 6 GB 19 DET 24
  7. 7 GB 23 DET 31
  8. 8 GB 20 DET 33
  9. 9 GB 13 DET 30
  10. 10 GB 10 DET 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.

The Packers won on an off day

They played far below what the matchup promised. In a fresh game against the Lions they would win 83% of the time; with this day’s form, 43%.

40 points apart for the Packers: the gap is how differently this game went from what the two teams usually are.

UnitThis gameUsual levelBetter or worse than usual
Packers offenseEPA per play gained +0.09 +0.13 worse by 0.04
Packers defenseEPA per play allowed −0.05 +0.10 better by 0.15
Lions offenseEPA per play gained −0.05 +0.08 worse by 0.14
Lions defenseEPA per play allowed +0.09 +0.14 better by 0.06

EPA (expected points added) per play on competitive snaps, turnovers left out because they are valued as luck. Usual level: the team’s earlier games this season plus half of last season, pulled toward the league average. One team’s defense and the other team’s offense are the same snaps, so one game can’t fully say whose day it was; it shows how far this one was from both teams’ norms.

How 4,000 replays ended

Packers win 43% of them, Lions 57%, counting the 3% still level after regulation as half each. The line is what actually happened: Packers by 3.

Show as a table
Final margin in the replaysShare of replays
Packers by 17+8.8%
Packers by 9–1612.3%
Packers by 1–819.4%
Level after regulation2.8%
Lions by 1–825.7%
Lions by 9–1616.0%
Lions by 17+15.0%

Where the luck was

Take the luck out

The final margin was Packers by 3. Remove the luck, one kind at a time, and it becomes Packers by 1.7.

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).

The kicks

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

  • M. Crosby, 32 yds made · 96% expected
  • M. Prater, 42 yds made · 86% expected
  • M. Crosby, 51 yds missed · 74% expected
  • M. Crosby, 40 yds made · 89% expected
  • M. Prater, 56 yds made · 65% expected
  • M. Crosby, 33 yds made · 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 0% and as high as 94%. 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 Q3 3:16 The Packers converted 3rd & 103rd & 4th downs · 27% expected +8% GB GB: Touchdown
2 Q4 6:40 The Packers were stopped on 3rd & 13rd & 4th downs · 73% expected +11% DET GB: Touchdown
3 Q4 5:24 The Packers converted 3rd & 103rd & 4th downs · 27% expected +23% GB GB: Touchdown
4 Q4 2:44 The Packers converted 3rd & 93rd & 4th downs · 29% expected +17% GB GB: Turnover
5 Q4 1:49 The Packers were stopped on 3rd & 203rd & 4th downs · 17% expected +10% DET GB: Field goal
6 Q4 1:32 The Lions were stopped on 3rd & 53rd & 4th downs · 40% expected +8% GB DET: Punt
7 Q4 1:20 Unnecessary Roughness on the Lions (Tavon Wilson), 15 yardsJudgment calls · 0 flags in 868 snaps before, position avg 1 per 441 +8% GB GB: Field goal
8 Q4 0:03 M. Crosby made 33-yard field goalKicks · 95% expected for him +20% GB –

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.

  • Marvin Jones (DET WR), out (IR) · 0.8 pts
  • T.J. Hockenson (DET TE), out (IR) · 0.7 pts
  • Jeff Driskel (DET QB), out (IR), replaced by d.blough · 0.5 pts
  • Jarrad Davis (DET LB), out (IR) · 0.3 pts
  • Jahlani Tavai (DET LB), out (IR) · 0.2 pts
  • A'Shawn Robinson (DET DT), out · 0.2 pts
  • Christian Jones (DET LB), out (IR) · 0.2 pts
  • Da'Shawn Hand (DET DE), out (IR) · 0.2 pts
  • Joe Dahl (DET G), out (IR) · 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

Packers 75% · Lions 25%

Final margin
Packers by 3
Luck in points
1.3 for the Packers
Luck-adjusted margin
Packers by 1.7
Replay with same day's form
Packers 43% · Lions 57% 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 2019 games · Packers · Lions

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