luckadjusted

Week 17 2021 · January 2, 2022

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

Giants at Bears, Week 17 2021: who deserved to win?

The Bears beat the Giants 29–3, and it was no fluke: replayed with the way both teams actually played, the Bears win 9 of 10.

Before kickoff the Bears were 70% favorites. The biggest swing (Q1, 14:54 left): the Giants fumbled and the Bears recovered, worth 11 points of win probability to the Bears.

Final

New York Giants 3
Chicago Bears 29

January 2, 2022 · Soldier Field · Closing line: Bears −7

Luck index +10 Bears about even · −10 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 1, Bears win 9.

  1. 1 NYG 16 CHI 10
  2. 2 NYG 17 CHI 20
  3. 3 NYG 6 CHI 12
  4. 4 NYG 7 CHI 15
  5. 5 NYG 3 CHI 13
  6. 6 NYG 10 CHI 23
  7. 7 NYG 12 CHI 28
  8. 8 NYG 17 CHI 37
  9. 9 NYG 10 CHI 33
  10. 10 NYG 6 CHI 36

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 10% of them, Bears 90%, counting the 2% still level after regulation as half each. The line is what actually happened: Bears by 26.

Show as a table
Final margin in the replaysShare of replays
Giants by 17+0.4%
Giants by 9–161.8%
Giants by 1–86.3%
Level after regulation2.0%
Bears by 1–817.7%
Bears by 9–1623.6%
Bears by 17+48.2%

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 +6.8 points to the Bears: the final margin was Bears by 26, without the luck Bears by 19.2. 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, 38 yds made · 87% expected
  • C. Santos, 21 yds made · 98% expected
  • C. Santos, 44 yds made · 75% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Giants 3 for 26 yards, Bears 5 for 35 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 4:45 Illegal Block Above the Waist on the Bears, 10 yards +1% NYG +0.9 pts
Q1 3:07 Offensive Holding on the Giants (Keion Crossen), 10 yards 0% CHI +0.8 pts
Q2 0:54 False Start on the Giants, 1 yard · pre-snap 0% CHI +0.2 pts
Q3 9:39 Defensive Pass Interference on the Giants (James Bradberry), 15 yards +1% CHI +2.2 pts
Q3 6:33 Offensive Holding on the Bears, 10 yards 0% NYG +0.9 pts
Q4 11:22 False Start on the Bears, 5 yards · pre-snap 0% NYG +0.1 pts
Q4 10:32 Illegal Contact on the Bears (Jaylon Johnson), 5 yards 0% NYG +0.9 pts
Q4 8:56 Defensive Holding on the Bears (Alec Ogletree), 5 yards 0% NYG +2.6 pts

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

When it happened

Bears’ 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 Bears were ahead in it, below while the Giants were.
#WhenWhat happenedWin probability forNext drive
1 Q1 14:54 The Giants fumbled and the Bears recoveredFumble bounces · loose balls are close to 50/50 +11% CHI NYG: Turnover
2 Q1 11:58 The Giants were stopped on 3rd & 23rd & 4th downs · 58% expected +5% CHI NYG: Punt
3 Q1 10:31 The Bears converted 3rd & 93rd & 4th downs · 26% expected +5% CHI CHI: Touchdown
4 Q1 8:14 The Bears converted 4th & 23rd & 4th downs · 48% expected +4% CHI CHI: Touchdown
5 Q1 5:23 The Giants were stopped on 3rd & 73rd & 4th downs · 32% expected +2% CHI NYG: Punt
6 Q2 10:26 The Giants converted 3rd & 43rd & 4th downs · 43% expected +3% NYG NYG: Field goal
7 Q2 5:02 The Bears converted 3rd & 23rd & 4th downs · 56% expected +2% CHI CHI: Field goal
8 Q2 1:04 C. Santos made 21-yard field goalKicks · 98% expected for him +3% NYG CHI: 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.

  • Duke Shelley (CHI CB), out · 0.2 pts
  • DeAndre Houston-Carson (CHI FS), out (IR) · 0.2 pts
  • Daniel Jones (NYG QB), out (IR), replaced by m.glennon · 1.9 pts
  • Dexter Lawrence (NYG DE), out (IR) · 0.9 pts
  • Darius Slayton (NYG WR), out (IR) · 0.7 pts
  • Sterling Shepard (NYG WR), out (IR) · 0.5 pts
  • Billy Price (NYG C), out · 0.4 pts
  • Kadarius Toney (NYG WR), out · 0.3 pts
  • Darnay Holmes (NYG CB), 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

Giants 0% · Bears 100%

Final margin
Bears by 26
Luck in points
6.8 for the Bears
Luck-adjusted margin
Bears by 19.2
Replay with same day's form
Giants 10% · Bears 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 17 2021 games · Giants · Bears

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