luckadjusted
NFL Week 9 · 2026

Week 4 2024 · September 29, 2024

Rams at Bears, Week 4 2024: who deserved to win?

The Bears beat the Rams 24–18, but the replays call it close to a coin flip: with the way both teams played, the Bears win 4 of 10. Luck ran their way: kicks alone were worth 16 points of win probability to the Bears.

Before kickoff the Bears were 59% favorites. The game turned on a luck play (Q2, 1:05 left): J. Karty missed a 43-yard field goal, worth 15 points of win probability to the Bears.

Final

Los Angeles Rams 18
Chicago Bears 24

September 29, 2024 · Soldier Field · Closing line: Bears −3

Luck index +56 Bears lucky · −56 Rams

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. Rams win 6, Bears win 4.

  1. 1 LA 28 CHI 6
  2. 2 LA 31 CHI 15
  3. 3 LA 30 CHI 20
  4. 4 LA 24 CHI 17
  5. 5 LA 24 CHI 20
  6. 6 LA 24 CHI 22
  7. 7 LA 20 CHI 23
  8. 8 LA 17 CHI 23
  9. 9 LA 14 CHI 26
  10. 10 LA 20 CHI 41

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

Rams win 56% of them, Bears 44%, counting the 6% still level after regulation as half each. The line is what actually happened: Bears by 6.

Show as a table
Final margin in the replaysShare of replays
Rams by 17+11.3%
Rams by 9–1615.9%
Rams by 1–823.1%
Level after regulation6.2%
Bears by 1–821.9%
Bears by 9–1613.5%
Bears by 17+8.3%

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 +7.7 points to the Bears: the final margin was Bears by 6, without the luck Rams by 1.7. 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.

  • J. Karty, 46 yds made · 74% expected
  • J. Karty, 37 yds made · 89% expected
  • J. Karty, 43 yds missed · 80% expected
  • C. Santos, 40 yds made · 86% expected
  • J. Karty, 25 yds made · 97% expected
  • J. Karty, 52 yds made · 62% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Rams 6 for 44 yards, Bears 10 for 84 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 15:00 Illegal Formation on the Bears (Tarvarius Moore), 5 yards · pre-snap +1% LA +0.4 pts
Q1 4:01 Illegal Blindside Block on the Bears, 15 yards +2% LA +1.2 pts
Q1 0:02 Encroachment on the Bears, 5 yards · pre-snap +1% LA +0.7 pts
Q2 15:00 Unnecessary Roughness on the Bears (Jaquan Brisker), 15 yards +4% LA +1.8 pts
Q2 15:00 False Start on the Rams, 5 yards · pre-snap +1% CHI +0.7 pts
Q2 12:13 False Start on the Bears, 5 yards · pre-snap +2% LA +0.5 pts
Q2 11:15 Offensive Holding on the Bears, 10 yards, wiping out the play +6% LA +1.8 pts
Q2 10:10 Defensive Holding on the Rams (Tre'Davious White), 5 yards, wiping out the play +7% CHI +1.7 pts
Q2 9:26 Defensive Holding on the Rams (Kamren Curl), 5 yards, wiping out the play +3% CHI +1.2 pts
Q2 8:12 Illegal Formation on the Bears, 5 yards, wiping out the play · pre-snap +7% LA +1.9 pts
Q2 5:52 Defensive Pass Interference on the Rams (Tre'Davious White), 14 yards +10% CHI +2.2 pts
Q2 1:20 Offensive Pass Interference on the Rams (Tutu Atwell), 10 yards +3% CHI +1.4 pts
Q3 12:24 Defensive Pass Interference on the Bears (Tyrique Stevenson), 14 yards +8% LA +1.5 pts
Q4 13:25 False Start on the Bears (Cole Kmet), 5 yards · pre-snap +2% LA +0.5 pts
Q4 7:25 False Start on the Bears (Cole Kmet), 5 yards · pre-snap +3% LA +0.8 pts
Q4 4:27 Player Out of Bounds on Kick on the Rams, 5 yards +2% CHI +0.5 pts

Rams penalties, every game · Bears penalties, every game · All teams, 2024

When it happened

Bears’ chance of winning

As low as 27% 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 Bears were ahead in it, below while the Rams were.
#WhenWhat happenedWin probability forNext drive
1 Q2 10:10 Defensive Holding on the Rams (Tre'Davious White), 5 yards, wiping out the playJudgment calls · 26 flags in 3761 snaps before, position avg 1 per 215 +7% CHI CHI: Punt
2 Q2 8:12 Illegal Formation on the Bears, 5 yards, wiping out the playPre-snap flags +7% LA LA: Turnover
3 Q2 6:51 The Rams fumbled and the Bears recoveredFumble bounces · loose balls are close to 50/50 +8% CHI LA: Missed field goal
4 Q2 5:52 Defensive Pass Interference on the Rams (Tre'Davious White), 14 yardsJudgment calls · 26 flags in 3761 snaps before, position avg 1 per 215 +10% CHI CHI: Touchdown
5 Q2 1:05 The game turned hereJ. Karty missed a 43-yard field goalKicks · 80% expected for him +15% CHI LA: End of half
6 Q3 12:24 Defensive Pass Interference on the Bears (Tyrique Stevenson), 14 yardsJudgment calls · 5 flags in 1152 snaps before, position avg 1 per 215 +8% LA LA: Field goal
7 Q4 14:55 The Rams’ two-point try failed3rd & 4th downs · 47% expected +7% CHI LA: Field goal
8 Q4 7:25 The Bears were stopped on 3rd & 73rd & 4th downs · 37% expectedFalse Start on the Bears (Cole Kmet), 5 yardsPre-snap flags · 15 flags in 3937 snaps before, position avg 1 per 280 +7% LA CHI: Punt

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.

  • Patrick Scales (CHI LS), out (IR) · 0.1 pts
  • Puka Nacua (LA WR), out (IR) · 1.6 pts
  • Cooper Kupp (LA WR), out · 1.3 pts
  • Tyler Higbee (LA TE), out (IR) · 0.7 pts
  • John Johnson (LA SS), out (IR) · 0.5 pts
  • Steve Avila (LA G), out (IR) · 0.4 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

Rams 42% · Bears 58%

Final margin
Bears by 6
Luck in points
7.7 for the Bears
Luck-adjusted margin
Rams by 1.7
Replay with same day's form
Rams 56% · Bears 44% 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; injuries from snap counts and injury reports.

Methodology and validation · All Week 4 2024 games · Rams · Bears

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