luckadjusted

Week 7 2019 · October 17, 2019

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

Chiefs at Broncos, Week 7 2019: who deserved to win?

The Chiefs beat the Broncos 30–6, and it was no fluke: replayed with the way both teams actually played, the Chiefs win 10 of 10. The Broncos had the bounces: injuries alone were worth 12 points of win probability to the Broncos.

An off day for the Broncos: their offense played far below its usual level. In a fresh game against the Chiefs they would win 36% of the time; with this day’s form, 2%. The numbers

Before kickoff the Chiefs were 59% favorites. The biggest swing (Q2, 7:17 left): Return touchdown by the Chiefs, worth 22 points of win probability to the Chiefs.

Final

Kansas City Chiefs 30
Denver Broncos 6

October 17, 2019 · Empower Field at Mile High · Closing line: Chiefs −3

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. Chiefs win 10, Broncos win 0.

  1. 1 KC 47 DEN 6
  2. 2 KC 41 DEN 9
  3. 3 KC 40 DEN 13
  4. 4 KC 34 DEN 10
  5. 5 KC 35 DEN 14
  6. 6 KC 38 DEN 21
  7. 7 KC 20 DEN 6
  8. 8 KC 24 DEN 13
  9. 9 KC 25 DEN 17
  10. 10 KC 27 DEN 24

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.

An off day for the Broncos

Their offense played far below its usual level. In a fresh game against the Chiefs they would win 36% of the time; with this day’s form, 2%.

34 points apart for the Broncos: the gap is how differently this game went from what the two teams usually are.

UnitThis gameUsual levelBetter or worse than usual
Chiefs offenseEPA per play gained −0.00 +0.28 worse by 0.28
Chiefs defenseEPA per play allowed −0.18 +0.16 better by 0.34
Broncos offenseEPA per play gained −0.18 +0.09 worse by 0.27
Broncos defenseEPA per play allowed −0.00 +0.11 better by 0.12

EPA (expected points added) per play on competitive snaps, turnovers left out because they are valued as luck. Usual level: the team’s earlier games this season plus half of last season, pulled toward the league average. One team’s defense and the other team’s offense are the same snaps, so one game can’t fully say whose day it was; it shows how far this one was from both teams’ norms.

How 4,000 replays ended

Chiefs win 98% of them, Broncos 2%. The line is what actually happened: Chiefs by 24.

Show as a table
Final margin in the replaysShare of replays
Chiefs by 17+84.2%
Chiefs by 9–1610.9%
Chiefs by 1–83.2%
Level after regulation0.3%
Broncos by 1–81.1%
Broncos by 9–160.4%
Broncos by 17+0.1%

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 +1.9 points to the Broncos: the final margin was Chiefs by 24, without the luck Chiefs by 25.9. 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, 33 yds made · 94% expected
  • H. Butker, 20 yds made · 99% expected
  • B. McManus, 45 yds missed · 80% expected
  • H. Butker, 39 yds made · 88% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Chiefs 6 for 46 yards, Broncos 4 for 33 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
Q1 13:40 Face Mask on the Chiefs (Frank Clark), 15 yards +5% DEN +1.8 pts
Q1 11:24 Defensive Holding on the Chiefs (Bashaud Breeland), 5 yards +6% DEN +1.5 pts
Q1 9:06 Encroachment on the Chiefs (Derrick Nnadi), 1 yard · pre-snap +2% DEN 0.0 pts
Q1 4:10 Offensive Holding on the Broncos, 10 yards +2% KC +1.2 pts
Q1 1:00 Defensive Holding on the Chiefs, 5 yards +2% DEN +0.9 pts
Q2 3:05 Defensive Holding on the Broncos (Duke Dawson), 5 yards, wiping out the play +4% KC +1.0 pts
Q2 0:35 Offensive Holding on the Broncos, 10 yards +1% KC +0.7 pts
Q3 8:37 Defensive Pass Interference on the Broncos, 8 yards +1% KC +1.6 pts
Q3 6:59 Offensive Pass Interference on the Chiefs (Byron Pringle), 10 yards, wiping out the play +4% DEN +3.0 pts
Q3 5:10 Illegal Block Above the Waist on the Chiefs (Tanoh Kpassagnon), 10 yards +2% DEN +0.9 pts

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

When it happened

Broncos’ chance of winning

As low as 0% and as high as 71%. 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 Chiefs were.
#WhenWhat happenedWin probability forNext drive
1 Q1 13:40 Face Mask on the Chiefs (Frank Clark), 15 yardsJudgment calls · 1 flag in 355 snaps before, position avg 1 per 249 +5% DEN DEN: Touchdown
2 Q1 11:24 Defensive Holding on the Chiefs (Bashaud Breeland), 5 yardsJudgment calls · 5 flags in 424 snaps before, position avg 1 per 199 +6% DEN DEN: Touchdown
3 Q1 6:19 The Chiefs converted 3rd & 33rd & 4th downs · 53% expected +7% KC KC: Touchdown
4 Q1 4:19 The Chiefs converted 3rd & 23rd & 4th downs · 62% expected +7% KC KC: Touchdown
5 Q2 15:00 The Broncos were stopped on 4th & 43rd & 4th downs · 41% expected +7% KC DEN: Opp touchdown
6 Q2 8:04 H. Butker made 20-yard field goalKicks · 99% expected for him +6% DEN KC: Opp touchdown
7 Q2 7:17 The Broncos fumbled and the Chiefs recoveredFumble bounces · loose balls are close to 50/50Return touchdown by the ChiefsSpecial teams +22% KC DEN: Missed field goal
8 Q2 5:44 The Broncos converted 3rd & 143rd & 4th downs · 18% expected +8% DEN DEN: Missed 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.

  • Tim Patrick (DEN WR), out (IR) · 0.5 pts
  • Bradley Chubb (DEN LB), out (IR) · 0.4 pts
  • Adam Gotsis (DEN DE), out · 0.3 pts
  • Eric Fisher (KC T), out · 1.3 pts
  • Sammy Watkins (KC WR), out · 0.9 pts
  • Chris Jones (KC DE), out · 0.9 pts
  • Chris Jones (KC DT), out · 0.8 pts
  • Andrew Wylie (KC T), out · 0.6 pts
  • Kendall Fuller (KC CB), out · 0.6 pts
  • Andrew Wylie (KC 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

Chiefs 100% · Broncos 0%

Final margin
Chiefs by 24
Luck in points
1.9 for the Broncos
Luck-adjusted margin
Chiefs by 25.9
Replay with same day's form
Chiefs 98% · Broncos 2% 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 (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 7 2019 games · Chiefs · Broncos

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