luckadjusted
NFL Week 9 · 2026

Week 13 2024 · November 28, 2024

Bears at Lions, Week 13 2024: who deserved to win?

The Lions beat the Bears 23–20, and the replays back it up: with the way both teams actually played, the Lions win 9 of 10.

Before kickoff the Lions were 76% favorites. The biggest swing (Q4, 1:04 left): Offensive Pass Interference on the Bears (Cole Kmet), 10 yards, wiping out the play, worth 40 points of win probability to the Lions.

Final

Chicago Bears 20
Detroit Lions 23

November 28, 2024 · Ford Field · Closing line: Lions −9.5

Luck index +14 Lions about even · −14 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, Lions win 9.

  1. 1 CHI 23 DET 17
  2. 2 CHI 17 DET 19
  3. 3 CHI 20 DET 24
  4. 4 CHI 20 DET 26
  5. 5 CHI 15 DET 24
  6. 6 CHI 16 DET 27
  7. 7 CHI 7 DET 21
  8. 8 CHI 0 DET 17
  9. 9 CHI 14 DET 35
  10. 10 CHI 6 DET 37

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 14% of them, Lions 86%, counting the 2% still level after regulation as half each. The line is what actually happened: Lions by 3.

Show as a table
Final margin in the replaysShare of replays
Bears by 17+0.8%
Bears by 9–162.7%
Bears by 1–89.3%
Level after regulation1.8%
Lions by 1–820.9%
Lions by 9–1626.5%
Lions by 17+38.0%

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 +2.5 points to the Bears: the final margin was Lions by 3, without the luck Lions 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.

  • J. Bates, 30 yds made · 97% expected
  • J. Bates, 36 yds made · 94% expected
  • J. Bates, 48 yds made · 80% expected
  • J. Bates, 45 yds missed · 86% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Bears 8 for 78 yards, Lions 6 for 79 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
Q2 13:39 Offensive Pass Interference on the Bears (Cole Kmet), 10 yards, wiping out the play +6% DET +2.4 pts
Q2 11:21 Illegal Crackback on the Lions (Jameson Williams), 15 yards +1% CHI +1.4 pts
Q2 10:59 Roughing the Passer on the Bears (Byron Cowart), 15 yards +3% DET +1.8 pts
Q2 9:00 Offensive Holding on the Lions (Amon-Ra St. Brown), 10 yards +2% CHI +1.7 pts
Q2 2:35 Offensive Holding on the Bears, 10 yards +2% DET +1.2 pts
Q2 1:05 Neutral Zone Infraction on the Bears (Darrell Taylor), 5 yards · pre-snap +1% DET +1.5 pts
Q2 0:31 Illegal Contact on the Lions (Jack Campbell), 5 yards +1% CHI +0.1 pts
Q3 7:43 Horse Collar Tackle on the Bears (Kyler Gordon), 15 yards +2% DET +1.7 pts
Q3 0:36 Defensive Holding on the Lions (Amik Robertson), 5 yards +1% CHI +1.0 pts
Q4 9:44 Taunting on the Lions (Jameson Williams), 15 yards +1% CHI +1.4 pts
Q4 3:31 Unsportsmanlike Conduct on the Bears (Keenan Allen), 3 yards +3% DET +0.3 pts
Q4 1:04 Offensive Pass Interference on the Bears (Cole Kmet), 10 yards, wiping out the play +40% DET +2.4 pts
Q4 0:56 Defensive Pass Interference on the Lions (Kindle Vildor), 29 yards +15% CHI +3.4 pts
Q4 0:43 Illegal Use of Hands on the Bears, 10 yards, wiping out the play +37% DET +2.1 pts

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

When it happened

Lions’ chance of winning

As low as 49% 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 Lions were ahead in it, below while the Bears were.
#WhenWhat happenedWin probability forNext drive
1 Q1 10:39 The Lions converted 3rd & 73rd & 4th downs · 37% expected +6% DET DET: Field goal
2 Q4 4:23 The Lions were stopped on 3rd & 13rd & 4th downs · 77% expected +7% CHI DET: Punt
3 Q4 3:14 The Bears converted 3rd & 73rd & 4th downs · 34% expected +10% CHI CHI: End of game
4 Q4 1:08 The Bears were stopped on 3rd & 43rd & 4th downs · 46% expected +12% DET CHI: End of game
5 Q4 1:04 Offensive Pass Interference on the Bears (Cole Kmet), 10 yards, wiping out the playJudgment calls · 17 flags in 4453 snaps before, position avg 1 per 280 +40% DET –
6 Q4 0:56 Defensive Pass Interference on the Lions (Kindle Vildor), 29 yardsJudgment calls · 15 flags in 2497 snaps before, position avg 1 per 215 +15% CHI CHI: End of game
7 Q4 0:43 Illegal Use of Hands on the Bears, 10 yards, wiping out the playJudgment calls +37% DET –
8 Q4 0:06 The Bears were stopped on 3rd & 263rd & 4th downs · 14% expected +10% DET –

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.

  • Taylor Decker (DET T), out · 1.1 pts
  • Aidan Hutchinson (DET DE), out (IR) · 0.8 pts
  • Carlton Davis (DET CB), out · 0.8 pts
  • Alex Anzalone (DET LB), out (IR) · 0.3 pts
  • Jaquan Brisker (CHI SS), out (IR) · 0.4 pts
  • Elijah Hicks (CHI FS), out · 0.3 pts
  • Ryan Bates (CHI C), out · 0.2 pts
  • Andrew Billings (CHI DT), 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

Bears 23% · Lions 77%

Final margin
Lions by 3
Luck in points
2.5 for the Bears
Luck-adjusted margin
Lions by 5.5
Replay with same day's form
Bears 14% · Lions 86% 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 13 2024 games · Bears · Lions

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