luckadjusted

Week 9 2021 · November 7, 2021

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

Packers at Chiefs, Week 9 2021: who deserved to win?

The Chiefs beat the Packers 13–7 and were the better team on the day: replayed with the same form, they win 7 of 10.

Before kickoff the Chiefs were 70% favorites. The biggest swing (Q2, 3:44 left): Defensive Offside on the Packers (Oren Burks), 5 yards, wiping out the play, worth 13 points of win probability to the Chiefs.

Final

Green Bay Packers 7
Kansas City Chiefs 13

November 7, 2021 · GEHA Field at Arrowhead Stadium · Closing line: Chiefs −7

Luck index +32 Chiefs lucky · −32 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 3, Chiefs win 7.

  1. 1 GB 30 KC 13
  2. 2 GB 28 KC 20
  3. 3 GB 30 KC 27
  4. 4 GB 10 KC 12
  5. 5 GB 12 KC 16
  6. 6 GB 27 KC 34
  7. 7 GB 6 KC 16
  8. 8 GB 24 KC 38
  9. 9 GB 12 KC 30
  10. 10 GB 0 KC 27

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 32% of them, Chiefs 68%, counting the 2% still level after regulation as half each. The line is what actually happened: Chiefs by 6.

Show as a table
Final margin in the replaysShare of replays
Packers by 17+4.8%
Packers by 9–168.9%
Packers by 1–818.2%
Level after regulation2.3%
Chiefs by 1–827.1%
Chiefs by 9–1620.1%
Chiefs by 17+18.6%

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 +19.9 points to the Chiefs: the final margin was Chiefs by 6, without the luck Packers by 13.9. 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, 40 yds missed · 86% expected
  • M. Crosby, 37 yds blocked · 90% expected
  • H. Butker, 24 yds made · 99% expected
  • H. Butker, 55 yds made · 63% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Packers 4 for 19 yards, Chiefs 6 for 33 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 9:26 Defensive Holding on the Packers (Rasul Douglas), 5 yards, wiping out the play +1% KC +0.6 pts
Q2 12:38 False Start on the Packers, 5 yards · pre-snap +1% KC +0.6 pts
Q2 6:17 Defensive Pass Interference on the Chiefs, 5 yards 0% GB +0.2 pts
Q2 3:44 Defensive Offside on the Packers (Oren Burks), 5 yards, wiping out the play · pre-snap +13% KC +6.3 pts
Q2 1:54 False Start on the Chiefs (Darrel Williams), 5 yards · pre-snap +2% GB +2.2 pts
Q3 4:54 Offensive Holding on the Chiefs, 10 yards 0% GB +0.9 pts
Q3 3:55 False Start on the Chiefs (Travis Kelce), 5 yards · pre-snap 0% GB +0.4 pts
Q3 0:49 Offensive Holding on the Packers, 4 yards, wiping out the play +3% KC +2.4 pts
Q4 12:48 Defensive Pass Interference on the Chiefs (Anthony Hitchens), 3 yards 0% GB +0.2 pts
Q4 2:00 False Start on the Chiefs, 5 yards · pre-snap 0% GB +0.2 pts

Packers penalties, every game · Chiefs penalties, every game · All teams, 2021

When it happened

Chiefs’ chance of winning

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 Chiefs were ahead in it, below while the Packers were.
#WhenWhat happenedWin probability forNext drive
1 Q1 14:08 The Packers were stopped on 3rd & 63rd & 4th downs · 40% expected +5% KC GB: Punt
2 Q1 12:37 The Chiefs converted 4th & 13rd & 4th downs · 76% expected +5% KC KC: Touchdown
3 Q1 0:52 M. Crosby missed 40-yard field goalKicks · 86% expected for him +6% KC GB: Missed field goal
4 Q2 15:00 The Chiefs were stopped on 4th & 13rd & 4th downs · 76% expected +8% GB KC: Punt
5 Q2 3:44 Defensive Offside on the Packers (Oren Burks), 5 yards, wiping out the playPre-snap flags · 0 flags in 1099 snaps before, position avg 1 per 409 +13% KC KC: Punt
6 Q2 2:50 The Packers fumbled and the Chiefs recoveredFumble bounces · loose balls are close to 50/50 +6% KC GB: Turnover on downs
7 Q2 0:30 The Packers were stopped on 4th & 53rd & 4th downs · 43% expected +5% KC GB: End of half
8 Q4 5:00 The Packers converted 4th & 53rd & 4th downs · 43% expected +8% 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.

  • Mike Remmers (KC T), out · 0.3 pts
  • Clyde Edwards-Helaire (KC RB), out (IR) · 0.2 pts
  • Aaron Rodgers (GB QB), out (IR), replaced by j.love · 9.0 pts
  • Jaire Alexander (GB CB), out (IR) · 0.9 pts
  • Josh Myers (GB C), out (IR) · 0.6 pts
  • Robert Tonyan (GB TE), out (IR) · 0.3 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 76% · Chiefs 24%

Final margin
Chiefs by 6
Luck in points
19.9 for the Chiefs
Luck-adjusted margin
Packers by 13.9
Replay with same day's form
Packers 32% · Chiefs 68% 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 9 2021 games · Packers · Chiefs

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