luckadjusted
NFL Week 9 · 2026

Week 15 2019 · December 15, 2019

No FTN charting for this game (drops and interception-worthy throws are not modelled).

Broncos at Chiefs, Week 15 2019: who deserved to win?

The Chiefs beat the Broncos 23–3, and the replays back it up: with the way both teams actually played, the Chiefs win 10 of 10.

Before kickoff the Chiefs were 77% favorites.

Final

Denver Broncos 3
Kansas City Chiefs 23

December 15, 2019 · Arrowhead Stadium · Closing line: Chiefs −10

Luck index +2 Chiefs about even · −2 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 0, Chiefs win 10.

  1. 1 DEN 17 KC 20
  2. 2 DEN 19 KC 25
  3. 3 DEN 0 KC 10
  4. 4 DEN 14 KC 26
  5. 5 DEN 20 KC 35
  6. 6 DEN 10 KC 27
  7. 7 DEN 7 KC 27
  8. 8 DEN 3 KC 26
  9. 9 DEN 3 KC 31
  10. 10 DEN 0 KC 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 2% of them, Chiefs 98%, counting the 1% still level after regulation as half each. The line is what actually happened: Chiefs by 20.

Show as a table
Final margin in the replaysShare of replays
Broncos by 17+0.1%
Broncos by 9–160.4%
Broncos by 1–81.3%
Level after regulation0.7%
Chiefs by 1–85.7%
Chiefs by 9–1615.7%
Chiefs by 17+76.3%

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 +4.4 points to the Broncos: the final margin was Chiefs by 20, without the luck Chiefs by 24.4. 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.

  • H. Butker, 23 yds made · 98% expected
  • H. Butker, 24 yds made · 98% expected
  • B. McManus, 32 yds made · 94% expected
  • H. Butker, 44 yds made · 79% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Broncos 7 for 72 yards, Chiefs 5 for 45 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 12:43 Delay of Game on the Broncos, 5 yards · pre-snap +1% KC +0.7 pts
Q1 12:15 Neutral Zone Infraction on the Chiefs (Armani Watts), 5 yards · pre-snap +1% DEN +0.5 pts
Q1 11:51 Ineligible Downfield Kick on the Broncos, 5 yards 0% KC +0.5 pts
Q1 11:42 Roughing the Passer on the Broncos (Shelby Harris), 15 yards +3% KC +1.3 pts
Q1 3:22 Defensive Offside on the Broncos (Jeremiah Attaochu), 5 yards · pre-snap +3% KC +0.8 pts
Q1 2:21 Defensive Pass Interference on the Broncos (Isaac Yiadom), 22 yards +2% KC +1.2 pts
Q2 12:02 False Start on the Broncos, 5 yards · pre-snap +1% KC +0.5 pts
Q2 1:22 Illegal Blindside Block on the Chiefs (Darwin Thompson), 15 yards +3% DEN +1.4 pts
Q2 0:44 Unnecessary Roughness on the Broncos (Justin Simmons), 15 yards +1% KC +1.2 pts
Q3 6:17 Face Mask on the Chiefs (Byron Pringle), 15 yards 0% DEN +1.2 pts
Q3 5:27 Defensive Holding on the Chiefs (Bashaud Breeland), 5 yards +1% DEN +0.8 pts
Q3 2:33 Defensive Holding on the Chiefs, 5 yards, wiping out the play +3% DEN +6.0 pts

Broncos penalties, every game · Chiefs penalties, every game · All teams, 2019

When it happened

Chiefs’ chance of winning

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 Chiefs were ahead in it, below while the Broncos were.
#WhenWhat happenedWin probability forNext drive
1 Q1 11:42 Roughing the Passer on the Broncos (Shelby Harris), 15 yardsJudgment calls · 0 flags in 554 snaps before, position avg 1 per 249 +3% KC KC: Touchdown
2 Q1 9:42 The Chiefs’ two-point try failed3rd & 4th downs · 47% expected +3% DEN KC: Field goal
3 Q1 8:23 The Broncos converted 3rd & 23rd & 4th downs · 57% expected +4% DEN DEN: Punt
4 Q1 5:42 The Broncos were stopped on 3rd & 53rd & 4th downs · 37% expected +3% KC DEN: Punt
5 Q1 3:22 Defensive Offside on the Broncos (Jeremiah Attaochu), 5 yardsPre-snap flags · 0 flags in 284 snaps before, position avg 1 per 393 +3% KC KC: Field goal
6 Q1 3:17 The Chiefs converted 3rd & 43rd & 4th downs · 48% expected +4% KC KC: Field goal
7 Q1 0:51 The Chiefs converted 3rd & 83rd & 4th downs · 34% expected +4% KC KC: Field goal
8 Q2 10:30 The Chiefs converted 3rd & 83rd & 4th downs · 34% expected +5% KC KC: Field goal

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.

  • Emmanuel Ogbah (KC DE), out (IR) · 0.5 pts
  • Martinas Rankin (KC T), out (IR) · 0.4 pts
  • Derek Wolfe (DEN DE), out (IR) · 0.7 pts
  • Ronald Leary (DEN G), out · 0.3 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% · Chiefs 100%

Final margin
Chiefs by 20
Luck in points
4.4 for the Broncos
Luck-adjusted margin
Chiefs by 24.4
Replay with same day's form
Broncos 2% · Chiefs 98% 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 (not available for this game); injuries from snap counts and injury reports. No FTN charting for this game (drops and interception-worthy throws are not modelled).

Methodology and validation · All Week 15 2019 games · Broncos · Chiefs

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