luckadjusted

Week 15 2023 · December 16, 2023

Broncos at Lions, Week 15 2023: who deserved to win?

The Lions beat the Broncos 42–17, and it was no fluke: replayed with the way both teams actually played, the Lions win 9 of 10. The Broncos had the bounces: judgment calls alone were worth 4.5 points to the Broncos.

Before kickoff the Lions were 66% favorites. The biggest swing (Q1, 11:49 left): the Broncos fumbled and the Lions recovered, worth 12 points of win probability to the Lions.

Final

Denver Broncos 17
Detroit Lions 42

December 16, 2023 · Ford Field · Closing line: Lions −5.5

Luck index +12 Lions about even · −12 Broncos

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. Broncos win 1, Lions win 9.

  1. 1 DEN 29 DET 24
  2. 2 DEN 28 DET 30
  3. 3 DEN 23 DET 28
  4. 4 DEN 19 DET 27
  5. 5 DEN 12 DET 23
  6. 6 DEN 13 DET 26
  7. 7 DEN 20 DET 37
  8. 8 DEN 6 DET 26
  9. 9 DEN 13 DET 37
  10. 10 DEN 5 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

Broncos win 12% of them, Lions 88%, counting the 2% still level after regulation as half each. The line is what actually happened: Lions by 25.

Show as a table
Final margin in the replaysShare of replays
Broncos by 17+1.2%
Broncos by 9–163.3%
Broncos by 1–87.7%
Level after regulation1.8%
Lions by 1–819.1%
Lions by 9–1623.5%
Lions by 17+43.3%

Where the luck was

Take the luck out

The final margin was Lions by 25. Remove the luck, one kind at a time, and it becomes Lions by 24.2.

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).

When it happened

Lions’ chance of winning

As low as 38% 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 Broncos were.
#WhenWhat happenedWin probability forNext drive
1 Q1 13:09 The Lions were stopped on 3rd & 63rd & 4th downs · 39% expected +5% DEN DET: Punt
2 Q1 11:49 The Broncos fumbled and the Lions recoveredFumble bounces · loose balls are close to 50/50 +12% DET DEN: Punt
3 Q1 10:30 The Lions were stopped on 3rd & 53rd & 4th downs · 43% expected +8% DEN DET: Punt
4 Q1 8:56 The Broncos got away with an interception-worthy throwInterceptions · 48% expected to stay out of the defense's hands +5% DEN DEN: Punt
5 Q1 7:58 Offensive Holding on the Lions, 10 yards, wiping out the playJudgment calls +8% DEN DEN: Punt
6 Q1 3:22 The Broncos converted 3rd & 93rd & 4th downs · 25% expected +8% DEN DEN: Punt
7 Q1 1:52 The Broncos were stopped on 3rd & 43rd & 4th downs · 41% expectedA. Trautman dropped a catchable passDrops · 0 drops on 43 catchable balls before this +7% DET DEN: Punt
8 Q2 13:53 The Lions converted 3rd & 53rd & 4th downs · 43% expected +7% DET DET: 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.

  • Alim McNeill (DET DT), out (IR) · 0.3 pts
  • Riley Patterson (DET K), out · 0.3 pts
  • Scott Daly (DET LS), out (IR) · 0.1 pts
  • Kareem Jackson (DEN SS), out (IR) · 0.5 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

Broncos 0% · Lions 100%

Final margin
Lions by 25
Luck in points
0.8 for the Lions
Luck-adjusted margin
Lions by 24.2
Replay with same day's form
Broncos 12% · Lions 88% 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 15 2023 games · Broncos · Lions

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