luckadjusted

Week 15 2024 · December 15, 2024

Colts at Broncos, Week 15 2024: who deserved to win?

The Broncos beat the Colts 31–13, but it was a coin flip: replayed with the way both teams played, the Broncos win 5 of 10. Luck ran their way: fumble bounces alone were worth 15 points of win probability to the Broncos.

Before kickoff the Broncos were 63% favorites. The biggest swing (Q4, 12:39 left): Return touchdown by the Broncos, worth 39 points of win probability to the Broncos.

Final

Indianapolis Colts 13
Denver Broncos 31

December 15, 2024 · Empower Field at Mile High · Closing line: Broncos −4.5

Luck index +52 Broncos lucky · −52 Colts

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. Colts win 5, Broncos win 5.

  1. 1 IND 33 DEN 10
  2. 2 IND 22 DEN 7
  3. 3 IND 23 DEN 13
  4. 4 IND 27 DEN 21
  5. 5 IND 17 DEN 15
  6. 6 IND 14 DEN 16
  7. 7 IND 10 DEN 16
  8. 8 IND 20 DEN 30
  9. 9 IND 20 DEN 35
  10. 10 IND 13 DEN 34

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

Colts win 52% of them, Broncos 48%, counting the 5% still level after regulation as half each. The line is what actually happened: Broncos by 18.

Show as a table
Final margin in the replaysShare of replays
Colts by 17+11.5%
Colts by 9–1616.3%
Colts by 1–820.8%
Level after regulation5.2%
Broncos by 1–820.3%
Broncos by 9–1615.6%
Broncos by 17+10.4%

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 Broncos: the final margin was Broncos by 18, without the luck Broncos by 12.4. 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, 37 yds made · 89% expected
  • M. Gay, 49 yds made · 69% expected
  • W. Lutz, 44 yds made · 77% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Colts 8 for 69 yards, Broncos 6 for 58 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 toward luck, pre-snap fouls mostly don’t. How calls are valued

WhenFlagWin probability for
Q2 11:51 Offensive Holding on the Colts, 4 yards +1% DEN +0.4 pts
Q2 6:14 Defensive Pass Interference on the Colts (Jaylon Jones), 10 yards 0% IND +0.5 pts
Q2 1:58 False Start on the Broncos, 5 yards · pre-snap +4% IND +0.5 pts
Q3 15:00 Defensive Holding on the Colts (Dayo Odeyingbo), 5 yards, wiping out the play +1% IND +0.2 pts
Q3 13:12 Unnecessary Roughness on the Broncos (Brandon Jones), 15 yards +3% IND +1.3 pts
Q3 9:46 Offensive Holding on the Colts, 10 yards +7% DEN +1.5 pts
Q3 5:18 Offensive Holding on the Colts, 10 yards +2% DEN +0.9 pts
Q3 3:57 Unnecessary Roughness on the Colts (Cameron McGrone), 15 yards +2% DEN +1.5 pts
Q3 3:47 False Start on the Broncos, 5 yards · pre-snap +2% IND +0.6 pts
Q4 13:16 Defensive Pass Interference on the Broncos (Cody Barton), 13 yards +4% IND +1.0 pts
Q4 12:39 Unsportsmanlike Conduct on the Broncos (Nik Bonitto), 15 yards +4% IND +1.2 pts
Q4 11:48 Illegal Use of Hands on the Broncos (Patrick Surtain II), 5 yards 0% IND +0.3 pts
Q4 8:11 Offensive Holding on the Colts, 10 yards, wiping out the play +2% DEN +1.3 pts
Q4 6:11 Defensive Offside on the Colts, 5 yards · pre-snap +3% DEN +2.4 pts

Colts penalties, every game · Broncos penalties, every game · All teams, 2024

When it happened

Broncos’ chance of winning

As low as 20% 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 Broncos were ahead in it, below while the Colts were.
#WhenWhat happenedWin probability forNext drive
1 Q1 13:45 The Colts converted 3rd & 103rd & 4th downs · 22% expected +9% IND IND: Touchdown
2 Q1 11:50 The Colts converted 3rd & 103rd & 4th downs · 22% expected +8% IND IND: Touchdown
3 Q2 7:23 The Broncos converted 3rd & 83rd & 4th downs · 29% expected +8% DEN DEN: Touchdown
4 Q2 1:58 The Broncos were stopped on 3rd & 73rd & 4th downs · 32% expectedFalse Start on the Broncos, 5 yardsPre-snap flags +8% IND DEN: Punt
5 Q2 0:10 M. Gay made 49-yard field goalKicks · 69% expected for him, 46 of 65 from 45+ before +8% IND IND: Turnover
6 Q3 13:18 The Broncos were stopped on 3rd & 13rd & 4th downs · 71% expectedThe Broncos threw an interception-worthy pass, and it was pickedInterceptions · 50% expected to stay out of the defense's hands +19% IND DEN: Punt
7 Q4 14:01 T. Franklin dropped a catchable passDrops · 1 drops on 26 catchable balls before this +8% IND DEN: Touchdown
8 Q4 12:39 The Colts fumbled and the Broncos recoveredFumble bounces · loose balls are close to 50/50Unsportsmanlike Conduct on the Broncos (Nik Bonitto), 15 yardsJudgment calls · 5 flags in 1479 snaps before, position avg 1 per 445Return touchdown by the BroncosSpecial teams +39% DEN IND: Turnover on downs

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.

  • Riley Moss (DEN CB), out · 0.6 pts
  • Braden Smith (IND T), out (IR) · 1.0 pts
  • Ryan Kelly (IND C), out (IR) · 0.6 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

Colts 2% · Broncos 98%

Final margin
Broncos by 18
Luck in points
5.5 for the Broncos
Luck-adjusted margin
Broncos by 12.5
Replay with same day's form
Colts 52% · Broncos 48% 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 2024 games · Colts · Broncos

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