luckadjusted

Week 9 2021 · November 7, 2021

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

Broncos at Cowboys, Week 9 2021: who deserved to win?

The Broncos beat the Cowboys 30–16, but it was a coin flip: replayed with the way both teams played, the Broncos win 5 of 10. Luck ran their way: 3rd & 4th downs alone were worth 8 points of win probability to the Broncos.

Before kickoff the Cowboys were 78% favorites. The biggest swing (Q1, 10:04 left): the Cowboys converted 3rd & 2, worth 10 points of win probability to the Cowboys.

Final

Denver Broncos 30
Dallas Cowboys 16

November 7, 2021 · AT&T Stadium · Closing line: Cowboys −10.5

Luck index +48 Broncos lucky · −48 Cowboys

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 5, Cowboys win 5.

  1. 1 DEN 37 DAL 14
  2. 2 DEN 35 DAL 21
  3. 3 DEN 39 DAL 30
  4. 4 DEN 24 DAL 19
  5. 5 DEN 27 DAL 24
  6. 6 DEN 38 DAL 40
  7. 7 DEN 26 DAL 32
  8. 8 DEN 23 DAL 33
  9. 9 DEN 26 DAL 40
  10. 10 DEN 19 DAL 42

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 52% of them, Cowboys 48%, counting the 5% still level after regulation as half each. The line is what actually happened: Broncos by 14.

Show as a table
Final margin in the replaysShare of replays
Broncos by 17+10.3%
Broncos by 9–1614.2%
Broncos by 1–823.8%
Level after regulation5.1%
Cowboys by 1–822.5%
Cowboys by 9–1613.9%
Cowboys by 17+10.2%

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 +6.9 points to the Broncos: the final margin was Broncos by 14, without the luck Broncos by 7.1. 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.

  • B. McManus, 53 yds made · 72% expected
  • B. McManus, 27 yds made · 99% expected
  • B. McManus, 53 yds missed · 72% expected
  • B. McManus, 42 yds made · 87% expected
  • Extra point missed · 93% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Broncos 5 for 37 yards, Cowboys 5 for 38 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 11:15 Defensive Offside on the Broncos (Stephen Weatherly), 5 yards · pre-snap +5% DAL +1.7 pts
Q1 3:30 False Start on the Broncos, 5 yards · pre-snap +1% DAL +0.5 pts
Q1 2:36 Defensive Pass Interference on the Cowboys (Trevon Diggs), 8 yards +7% DEN +2.1 pts
Q2 10:48 Offensive Holding on the Broncos, 10 yards, wiping out the play +3% DAL +2.2 pts
Q2 1:48 Illegal Block Above the Waist on the Broncos (Justin Strnad), 10 yards +1% DAL +1.0 pts
Q2 0:13 Defensive Holding on the Cowboys (Trevon Diggs), 5 yards, wiping out the play +6% DEN +2.9 pts
Q3 3:48 Offensive Holding on the Broncos, 7 yards, wiping out the play +1% DAL +2.4 pts
Q4 11:18 Illegal Use of Hands on the Cowboys, 10 yards 0% DEN +1.1 pts
Q4 10:48 Offensive Holding on the Cowboys, 10 yards, wiping out the play +1% DEN +4.1 pts
Q4 4:49 False Start on the Cowboys, 5 yards · pre-snap 0% DEN +0.9 pts

Broncos penalties, every game · Cowboys penalties, every game · All teams, 2021

When it happened

Cowboys’ chance of winning

As low as 0% and as high as 65%. 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 Cowboys were ahead in it, below while the Broncos were.
#WhenWhat happenedWin probability forNext drive
1 Q1 13:39 The Cowboys were stopped on 4th & 13rd & 4th downs · 73% expected +8% DEN DAL: Turnover on downs
2 Q1 12:08 The Cowboys fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +6% DAL DAL: Turnover on downs
3 Q1 10:04 The Cowboys converted 3rd & 23rd & 4th downs · 60% expected +10% DAL DAL: Turnover on downs
4 Q1 8:12 The Cowboys were stopped on 4th & 23rd & 4th downs · 60% expected +8% DEN DAL: Punt
5 Q1 7:03 The Broncos converted 3rd & 23rd & 4th downs · 60% expected +8% DEN DEN: Touchdown
6 Q1 2:36 Defensive Pass Interference on the Cowboys (Trevon Diggs), 8 yardsJudgment calls · 9 flags in 1188 snaps before, position avg 1 per 213 +7% DEN DEN: Touchdown
7 Q1 0:09 The Cowboys were stopped on 3rd & 13rd & 4th downs · 73% expected +5% DEN DAL: Punt
8 Q2 0:13 Defensive Holding on the Cowboys (Trevon Diggs), 5 yards, wiping out the playJudgment calls · 9 flags in 1188 snaps before, position avg 1 per 213 +6% DEN DEN: End of half

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.

  • Tyron Smith (DAL T), out · 1.2 pts
  • Michael Gallup (DAL WR), out (IR) · 0.8 pts
  • Blake Jarwin (DAL TE), out (IR) · 0.3 pts
  • Garett Bolles (DEN T), out · 1.0 pts
  • Noah Fant (DEN TE), out (IR) · 1.0 pts
  • Bryce Callahan (DEN CB), out (IR) · 0.4 pts
  • Josey Jewell (DEN LB), out (IR) · 0.3 pts
  • Malik Reed (DEN LB), 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 78% · Cowboys 22%

Final margin
Broncos by 14
Luck in points
6.9 for the Broncos
Luck-adjusted margin
Broncos by 7.1
Replay with same day's form
Broncos 52% · Cowboys 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 (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 9 2021 games · Broncos · Cowboys

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