luckadjusted

Week 2 2020 · September 20, 2020

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

Lions at Packers, Week 2 2020: who deserved to win?

The Packers beat the Lions 42–21 and were the better team on the day: replayed with the same form, they win 8 of 10.

Before kickoff the Packers were 70% favorites. The biggest swing (Q2, 10:13 left): the Packers converted 3rd & 3, worth 10 points of win probability to the Packers.

Final

Detroit Lions 21
Green Bay Packers 42

September 20, 2020 · Lambeau Field · Closing line: Packers −7

Luck index +25 Packers about even · −25 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 2, Packers win 8.

  1. 1 DET 34 GB 20
  2. 2 DET 27 GB 23
  3. 3 DET 21 GB 23
  4. 4 DET 30 GB 34
  5. 5 DET 20 GB 27
  6. 6 DET 10 GB 20
  7. 7 DET 14 GB 26
  8. 8 DET 17 GB 33
  9. 9 DET 20 GB 41
  10. 10 DET 5 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 25% of them, Packers 75%, counting the 4% still level after regulation as half each. The line is what actually happened: Packers by 21.

Show as a table
Final margin in the replaysShare of replays
Lions by 17+3.8%
Lions by 9–167.0%
Lions by 1–813.7%
Level after regulation4.0%
Packers by 1–823.6%
Packers by 9–1621.2%
Packers by 17+26.6%

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 +9.6 points to the Packers: the final margin was Packers by 21, without the luck Packers by 11.4. 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.

  • M. Crosby, 43 yds made · 81% expected
  • M. Prater, 57 yds missed · 56% expected
  • M. Crosby, 35 yds made · 92% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Lions 7 for 70 yards, Packers 8 for 60 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 13:17 Unnecessary Roughness on the Packers (Za'Darius Smith), 15 yards +5% DET +1.5 pts
Q1 0:04 Defensive Offside on the Packers (Montravius Adams), 5 yards · pre-snap +1% DET +0.5 pts
Q2 15:00 Defensive Holding on the Lions (Amani Oruwariye), 5 yards +2% GB +0.6 pts
Q2 7:28 Unnecessary Roughness on the Lions, 15 yards +5% GB +1.4 pts
Q2 3:22 Offensive Holding on the Packers, 10 yards +5% DET +1.1 pts
Q2 1:54 Delay of Game on the Packers, 5 yards · pre-snap +3% DET +0.4 pts
Q2 1:00 Unnecessary Roughness on the Lions (Will Harris), 15 yards +2% GB +1.0 pts
Q2 0:54 Horse Collar Tackle on the Lions (Will Harris), 15 yards +7% GB +1.8 pts
Q2 0:03 Neutral Zone Infraction on the Packers (Preston Smith), 5 yards · pre-snap +1% DET +0.9 pts
Q3 12:28 False Start on the Packers (Marquez Valdes-Scantling), 5 yards · pre-snap +1% DET +0.6 pts
Q3 9:47 Offensive Holding on the Packers, 10 yards +2% DET +1.1 pts
Q3 8:45 Unnecessary Roughness on the Lions (Jamal Agnew), 5 yards +1% GB +0.5 pts
Q3 1:54 Defensive Holding on the Lions (Darryl Roberts), 5 yards 0% GB +0.7 pts
Q4 12:09 Illegal Shift on the Packers, 5 yards, wiping out the play · pre-snap +1% DET +1.4 pts
Q4 7:53 Intentional Grounding on the Lions (Matthew Stafford), 10 yards 0% GB +1.1 pts

Lions penalties, every game · Packers penalties, every game · All teams, 2020

When it happened

Packers’ chance of winning

As low as 24% 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 8:26 The Packers converted 3rd & 83rd & 4th downs · 35% expected +6% GB GB: Field goal
2 Q1 6:53 The Packers converted 4th & 63rd & 4th downs · 40% expected +8% GB GB: Field goal
3 Q1 3:19 The Lions converted 3rd & 23rd & 4th downs · 60% expected +6% DET DET: Touchdown
4 Q2 10:13 The Packers converted 3rd & 33rd & 4th downs · 47% expected +10% GB GB: Touchdown
5 Q2 8:13 The Lions converted 3rd & 103rd & 4th downs · 27% expected +8% DET DET: Punt
6 Q2 0:54 Horse Collar Tackle on the Lions (Will Harris), 15 yardsJudgment calls · 2 flags in 990 snaps before, position avg 1 per 510 +7% GB GB: Touchdown
7 Q2 0:03 M. Prater missed 57-yard field goalKicks · 56% expected for him, 10 of 14 from 45+ beforeNeutral Zone Infraction on the Packers (Preston Smith), 5 yardsPre-snap flags · 3 flags in 1050 snaps before, position avg 1 per 395 +10% GB DET: Punt
8 Q3 8:37 Return touchdown by the PackersSpecial teams +7% GB GB: Opp 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.

  • Kenny Clark (GB NT), out · 0.5 pts
  • Billy Turner (GB G), out · 0.3 pts
  • Kenny Golladay (DET WR), out · 0.9 pts
  • Justin Coleman (DET CB), out (IR) · 0.4 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

Lions 1% · Packers 99%

Final margin
Packers by 21
Luck in points
9.6 for the Packers
Luck-adjusted margin
Packers by 11.4
Replay with same day's form
Lions 25% · Packers 75% 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 2020 games · Lions · Packers

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