luckadjusted
NFL Week 9 · 2026

Week 1 2021 · September 12, 2021

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

Bears at Rams, Week 1 2021: who deserved to win?

The Rams beat the Bears 34–14, and the replays back it up: with the way both teams actually played, the Rams win 9 of 10.

Before kickoff the Rams were 76% favorites.

Final

Chicago Bears 14
Los Angeles Rams 34

September 12, 2021 · SoFi Stadium · Closing line: Rams −9.5

Luck index +11 Rams about even · −11 Bears

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. Bears win 1, Rams win 9.

  1. 1 CHI 13 LA 7
  2. 2 CHI 17 LA 20
  3. 3 CHI 19 LA 24
  4. 4 CHI 7 LA 16
  5. 5 CHI 13 LA 24
  6. 6 CHI 6 LA 19
  7. 7 CHI 3 LA 19
  8. 8 CHI 7 LA 26
  9. 9 CHI 14 LA 38
  10. 10 CHI 15 LA 47

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

Bears win 11% of them, Rams 89%, counting the 2% still level after regulation as half each. The line is what actually happened: Rams by 20.

Show as a table
Final margin in the replaysShare of replays
Bears by 17+0.7%
Bears by 9–162.5%
Bears by 1–87.2%
Level after regulation2.0%
Rams by 1–819.1%
Rams by 9–1625.6%
Rams by 17+43.0%

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 +5.5 points to the Rams: the final margin was Rams by 20, without the luck Rams by 14.5. 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.

  • M. Gay, 53 yds made · 70% expected
  • M. Gay, 22 yds made · 98% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Bears 3 for 35 yards, Rams 4 for 36 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 half toward luck; pre-snap fouls, which repeat, don’t count. How calls are valued

WhenFlagWin probability for
Q1 12:26 False Start on the Bears (Cole Kmet), 5 yards · pre-snap +4% LA +1.4 pts
Q1 3:58 Face Mask on the Rams (David Long), 15 yards +2% CHI +1.8 pts
Q2 5:49 Delay of Game on the Rams, 1 yard · pre-snap 0% CHI +0.1 pts
Q3 14:01 Roughing the Passer on the Bears (Akiem Hicks), 15 yards +4% LA +1.0 pts
Q4 8:37 Taunting on the Bears (Alec Ogletree), 15 yards +1% LA +1.4 pts
Q4 6:49 Offensive Holding on the Rams, 10 yards 0% CHI +1.6 pts
Q4 5:53 Offensive Holding on the Rams (Johnny Mundt), 10 yards 0% CHI +1.4 pts

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

When it happened

Rams’ chance of winning

As low as 41% 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 Rams were ahead in it, below while the Bears were.
#WhenWhat happenedWin probability forNext drive
1 Q1 12:26 False Start on the Bears (Cole Kmet), 5 yardsPre-snap flags · 3 flags in 753 snaps before, position avg 1 per 269 +4% LA LA: Touchdown
2 Q1 7:21 The Bears were stopped on 4th & 43rd & 4th downs · 47% expected +4% LA CHI: Turnover
3 Q2 14:40 The Rams were stopped on 3rd & 13rd & 4th downs · 76% expected +3% CHI LA: Field goal
4 Q2 13:56 The Rams converted 4th & 13rd & 4th downs · 77% expected +3% LA LA: Field goal
5 Q3 14:30 The Rams converted 3rd & 103rd & 4th downs · 30% expected +7% LA LA: Touchdown
6 Q3 14:01 Roughing the Passer on the Bears (Akiem Hicks), 15 yardsJudgment calls · 10 flags in 1055 snaps before, position avg 1 per 273 +4% LA LA: Touchdown
7 Q3 5:08 The Bears converted 3rd & 83rd & 4th downs · 32% expected +4% CHI CHI: Touchdown
8 Q3 3:51 The Rams converted 3rd & 53rd & 4th downs · 44% expected +5% LA LA: 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.

  • Cam Akers (LA RB), out (IR) · 0.1 pts
  • Danny Trevathan (CHI LB), out (IR) · 0.3 pts
  • Duke Shelley (CHI DB), out · 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

Bears 0% · Rams 100%

Final margin
Rams by 20
Luck in points
5.5 for the Rams
Luck-adjusted margin
Rams by 14.5
Replay with same day's form
Bears 11% · Rams 89% unchanged: why
How much of each is luck?

0% treats it as skill, 100% as pure luck. The tick is our fit.

What counts

None by default: our tests measured no carryover after a lucky break. Slide it up to count a break for more than its own swing. 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 1 2021 games · Bears · Rams

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