luckadjusted

Week 13 2024 · November 28, 2024

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

The Lions beat the Bears 23–20, and it was no fluke: replayed with the way both teams actually played, the Lions win 9 of 10. The Bears had the bounces: kicks alone were worth 2.6 points to the Bears.

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 30 DET 24
  2. 2 CHI 10 DET 12
  3. 3 CHI 19 DET 24
  4. 4 CHI 15 DET 23
  5. 5 CHI 21 DET 31
  6. 6 CHI 17 DET 31
  7. 7 CHI 13 DET 30
  8. 8 CHI 14 DET 34
  9. 9 CHI 10 DET 35
  10. 10 CHI 12 DET 44

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 1% 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+0.9%
Bears by 9–163.5%
Bears by 1–89.4%
Level after regulation1.3%
Lions by 1–824.9%
Lions by 9–1622.4%
Lions by 17+37.4%

Where the luck was

Take the luck out

The final margin was Lions by 3. Remove the luck, one kind at a time, and it becomes Lions by 6.4.

Each row takes one kind of luck out of the margin. Color shows which team it helped. Luck shares are the fitted ones (how much of each component 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 · 81% expected
  • J. Bates, 45 yds missed · 85% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

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 Q4 5:42 The Bears converted 3rd & 13rd & 4th downs · 72% expected +12% CHI CHI: Touchdown
2 Q4 4:23 The Lions were stopped on 3rd & 13rd & 4th downs · 75% expected +7% CHI DET: Punt
3 Q4 3:14 The Bears converted 3rd & 73rd & 4th downs · 32% expected +12% CHI CHI: End of game
4 Q4 1:08 The Bears were stopped on 3rd & 43rd & 4th downs · 44% expected +13% 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 +34% 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 · 13% expected +19% 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
  • Andrew Billings (CHI DT), out (IR) · 0.2 pts
  • Ryan Bates (CHI C), 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 30% · Lions 70%

Final margin
Lions by 3
Luck in points
3.4 for the Bears
Luck-adjusted margin
Lions by 6.4
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

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; injuries from snap counts and injury reports.

Methodology and validation · All Week 13 2024 games · Bears · Lions

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