luckadjusted

Week 8 2021 · November 1, 2021

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

Giants at Chiefs, Week 8 2021: who deserved to win?

The Chiefs beat the Giants 20–17, and it was no fluke: replayed with the way both teams actually played, the Chiefs win 8 of 10.

Before kickoff the Chiefs were 78% favorites. The biggest swing (Q4, 4:29 left): Defensive Offside on the Giants (Oshane Ximines), 5 yards, wiping out the play, worth 40 points of win probability to the Chiefs.

Final

New York Giants 17
Kansas City Chiefs 20

November 1, 2021 · GEHA Field at Arrowhead Stadium · Closing line: Chiefs −10.5

Luck index +19 Chiefs about even · −19 Giants

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. Giants win 2, Chiefs win 8.

  1. 1 NYG 25 KC 13
  2. 2 NYG 20 KC 17
  3. 3 NYG 19 KC 20
  4. 4 NYG 16 KC 20
  5. 5 NYG 20 KC 28
  6. 6 NYG 24 KC 35
  7. 7 NYG 10 KC 24
  8. 8 NYG 16 KC 33
  9. 9 NYG 27 KC 48
  10. 10 NYG 17 KC 45

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

Giants win 19% of them, Chiefs 81%, counting the 1% still level after regulation as half each. The line is what actually happened: Chiefs by 3.

Show as a table
Final margin in the replaysShare of replays
Giants by 17+2.1%
Giants by 9–164.7%
Giants by 1–812.3%
Level after regulation1.1%
Chiefs by 1–822.1%
Chiefs by 9–1621.2%
Chiefs by 17+36.4%

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 +2.5 points to the Giants: the final margin was Chiefs by 3, without the luck Chiefs by 5.5. 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.

  • G. Gano, 23 yds made · 100% expected
  • H. Butker, 36 yds made · 92% expected
  • H. Butker, 34 yds made · 94% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Giants 10 for 88 yards, Chiefs 12 for 103 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
Q2 6:37 Taunting on the Giants (Collin Johnson), 8 yards +2% KC +0.7 pts
Q2 4:46 Roughing the Passer on the Chiefs (L'Jarius Sneed), 13 yards +4% NYG +1.4 pts
Q2 2:09 Intentional Grounding on the Chiefs (Patrick Mahomes), 10 yards +3% NYG +1.2 pts
Q2 2:05 Defensive Offside on the Giants (Leonard Williams), 5 yards · pre-snap +1% KC 0.0 pts
Q2 1:46 Unnecessary Roughness on the Chiefs (Marcus Kemp), 15 yards +5% NYG +1.6 pts
Q2 0:25 Defensive Pass Interference on the Chiefs (L'Jarius Sneed), 8 yards +1% NYG +0.2 pts
Q2 0:21 Offensive Holding on the Giants, 10 yards +3% KC +0.6 pts
Q2 0:21 False Start on the Giants, 5 yards · pre-snap +1% KC +0.2 pts
Q2 0:05 Delay of Game on the Giants, 5 yards · pre-snap 0% KC +0.2 pts
Q3 12:51 Offensive Holding on the Chiefs (Jarran Reed), 7 yards +2% NYG +0.8 pts
Q3 4:11 Offensive Holding on the Chiefs, 10 yards, wiping out the play +5% NYG +2.2 pts
Q3 2:50 Defensive Holding on the Chiefs (Chris Jones), 5 yards +4% NYG +0.5 pts
Q3 1:47 Defensive Offside on the Chiefs (Chris Jones), 5 yards · pre-snap +1% NYG +0.3 pts
Q4 14:53 Offensive Holding on the Chiefs (Byron Pringle), 10 yards +3% NYG +0.6 pts
Q4 14:53 Illegal Formation on the Chiefs (Derrick Nnadi), 5 yards · pre-snap +3% NYG +0.6 pts
Q4 11:58 Unnecessary Roughness on the Giants (Tae Crowder), 15 yards +12% KC +2.0 pts
Q4 7:28 Taunting on the Giants (Elijhaa Penny), 15 yards +12% KC +1.0 pts
Q4 5:48 Defensive Holding on the Chiefs, 5 yards +5% NYG +1.1 pts
Q4 4:49 Illegal Touch Kick on the Giants (Cam Brown), 5 yards +4% KC +0.3 pts
Q4 4:41 Offensive Holding on the Chiefs, 10 yards +3% NYG +0.8 pts
Q4 4:29 Defensive Offside on the Giants (Oshane Ximines), 5 yards, wiping out the play · pre-snap +40% KC +4.6 pts
Q4 4:22 Face Mask on the Giants (Tae Crowder), 15 yards +8% KC +2.0 pts

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

When it happened

Chiefs’ chance of winning

As low as 39% 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 Chiefs were ahead in it, below while the Giants were.
#WhenWhat happenedWin probability forNext drive
1 Q1 8:27 The Chiefs were stopped on 3rd & 53rd & 4th downs · 37% expected +14% NYG KC: Touchdown
2 Q1 1:56 The Giants converted 3rd & 113rd & 4th downs · 26% expected +10% NYG NYG: Touchdown
3 Q2 14:19 The Giants converted 4th & 13rd & 4th downs · 66% expected +13% NYG NYG: Touchdown
4 Q4 14:57 The Giants converted 3rd & 43rd & 4th downs · 37% expected +9% NYG NYG: Touchdown
5 Q4 11:58 Unnecessary Roughness on the Giants (Tae Crowder), 15 yardsJudgment calls · 1 flag in 896 snaps before, position avg 1 per 409 +12% KC KC: Field goal
6 Q4 11:04 The Chiefs converted 3rd & 113rd & 4th downs · 30% expected +10% KC KC: Field goal
7 Q4 7:28 The Giants converted 3rd & 13rd & 4th downs · 74% expectedTaunting on the Giants (Elijhaa Penny), 15 yardsJudgment calls · 3 flags in 840 snaps before, position avg 1 per 773 +9% KC NYG: Punt
8 Q4 4:29 Defensive Offside on the Giants (Oshane Ximines), 5 yards, wiping out the playPre-snap flags · 1 flag in 1137 snaps before, position avg 1 per 409 +40% KC KC: Field goal

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 · 0.6 pts
  • Anthony Hitchens (KC LB), out · 0.4 pts
  • Clyde Edwards-Helaire (KC RB), out (IR) · 0.2 pts
  • Andrew Thomas (NYG T), out (IR) · 0.9 pts
  • Kenny Golladay (NYG WR), out · 0.8 pts
  • Saquon Barkley (NYG RB), out · 0.6 pts
  • Blake Martinez (NYG LB), out (IR) · 0.4 pts
  • Nick Gates (NYG C), out (IR) · 0.4 pts
  • Jabrill Peppers (NYG SS), out (IR) · 0.3 pts
  • Lorenzo Carter (NYG LB), 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

Giants 11% · Chiefs 89%

Final margin
Chiefs by 3
Luck in points
2.5 for the Giants
Luck-adjusted margin
Chiefs by 5.5
Replay with same day's form
Giants 19% · Chiefs 81% 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 8 2021 games · Giants · Chiefs

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