luckadjusted
NFL Week 9 · 2026

Week 5 2021 · October 10, 2021

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

Broncos at Steelers, Week 5 2021: who deserved to win?

The Steelers beat the Broncos 27–19, but the replays call it close to a coin flip: with the way both teams played, the Steelers win 5 of 10.

Before kickoff the Broncos were 56% favorites. The biggest swing (Q2, 3:03 left): Defensive Pass Interference on the Broncos (Kyle Fuller), 17 yards, worth 8 points of win probability to the Steelers.

Final

Denver Broncos 19
Pittsburgh Steelers 27

October 10, 2021 · Heinz Field · Closing line: Broncos −2

Luck index +51 Steelers lucky · −51 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 5, Steelers win 5.

  1. 1 DEN 31 PIT 10
  2. 2 DEN 31 PIT 17
  3. 3 DEN 30 PIT 20
  4. 4 DEN 20 PIT 14
  5. 5 DEN 16 PIT 13
  6. 6 DEN 15 PIT 17
  7. 7 DEN 20 PIT 24
  8. 8 DEN 20 PIT 27
  9. 9 DEN 9 PIT 20
  10. 10 DEN 10 PIT 30

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 51% of them, Steelers 49%, counting the 7% still level after regulation as half each. The line is what actually happened: Steelers by 8.

Show as a table
Final margin in the replaysShare of replays
Broncos by 17+9.2%
Broncos by 9–1614.6%
Broncos by 1–823.5%
Level after regulation6.6%
Steelers by 1–823.3%
Steelers by 9–1614.2%
Steelers by 17+8.6%

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 +3.2 points to the Steelers: the final margin was Steelers by 8, without the luck Steelers by 4.8. 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, 39 yds made · 90% expected
  • C. Boswell, 48 yds made · 76% expected
  • B. McManus, 29 yds made · 97% expected
  • C. Boswell, 43 yds made · 84% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Broncos 7 for 67 yards, Steelers 8 for 59 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 15:00 Offensive Holding on the Steelers (Benny Snell Jr.), 10 yards +1% DEN +0.8 pts
Q1 12:02 Delay of Game on the Broncos, 5 yards · pre-snap +2% PIT +0.8 pts
Q1 5:17 False Start on the Steelers, 5 yards · pre-snap +1% DEN +0.5 pts
Q2 11:54 Illegal Block Above the Waist on the Steelers (Justin Layne), 9 yards +2% DEN +0.8 pts
Q2 8:08 Delay of Game on the Broncos (Javonte Williams), 5 yards · pre-snap +2% PIT +0.8 pts
Q2 3:35 False Start on the Steelers, 5 yards · pre-snap +2% DEN +0.8 pts
Q2 3:03 Defensive Pass Interference on the Broncos (Kyle Fuller), 17 yards +8% PIT +2.9 pts
Q2 1:55 False Start on the Broncos, 5 yards · pre-snap +1% PIT +0.5 pts
Q2 1:46 Neutral Zone Infraction on the Steelers (Alex Highsmith), 5 yards · pre-snap +1% DEN +0.5 pts
Q2 0:59 Ineligible Downfield Pass on the Steelers, 5 yards, wiping out the play +4% DEN +1.0 pts
Q3 15:00 Offensive Holding on the Broncos, 10 yards +1% PIT +0.9 pts
Q3 7:48 Offensive Holding on the Steelers, 10 yards +2% DEN +1.1 pts
Q3 2:58 Leverage on the Broncos (Dre'Mont Jones), 15 yards +5% PIT +3.5 pts
Q4 11:34 Offensive Holding on the Broncos, 10 yards 0% PIT +1.5 pts
Q4 9:28 Offensive Holding on the Steelers, 10 yards +1% DEN +1.4 pts

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

When it happened

Steelers’ 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 Steelers were ahead in it, below while the Broncos were.
#WhenWhat happenedWin probability forNext drive
1 Q1 12:09 The Steelers converted 3rd & 73rd & 4th downs · 35% expected +7% PIT PIT: Touchdown
2 Q1 4:08 The Steelers fumbled and the Broncos recoveredFumble bounces · loose balls are close to 50/50 +7% DEN PIT: Field goal
3 Q2 12:46 C. Boswell made a 48-yard field goalKicks · 76% expected for him, 13 of 15 from 45+ before +7% PIT PIT: Punt
4 Q2 3:03 Defensive Pass Interference on the Broncos (Kyle Fuller), 17 yardsJudgment calls · 17 flags in 2610 snaps before, position avg 1 per 213 +8% PIT PIT: Touchdown
5 Q3 2:58 Leverage on the Broncos (Dre'Mont Jones), 15 yardsJudgment calls · 6 flags in 1272 snaps before, position avg 1 per 266 +5% PIT PIT: Touchdown
6 Q4 2:33 C. Boswell made a 43-yard field goalKicks · 84% expected for him +4% PIT PIT: End of game
7 Q4 1:03 The Broncos converted 3rd & 53rd & 4th downs · 42% expected +7% DEN DEN: Turnover
8 Q4 0:22 The Broncos were stopped on 3rd & 33rd & 4th downs · 45% expected +5% PIT DEN: Turnover

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.

  • Stephon Tuitt (PIT DE), out (IR) · 0.9 pts
  • Cameron Sutton (PIT CB), out · 0.5 pts
  • Tyson Alualu (PIT DE), out (IR) · 0.4 pts
  • Jerry Jeudy (DEN WR), out (IR) · 0.7 pts
  • Bradley Chubb (DEN OLB), out (IR) · 0.6 pts
  • Josey Jewell (DEN ILB), out (IR) · 0.4 pts
  • Michael Ojemudia (DEN CB), out (IR) · 0.4 pts
  • Josey Jewell (DEN LB), out (IR) · 0.3 pts
  • DaeSean Hamilton (DEN WR), out (IR) · 0.2 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 14% · Steelers 86%

Final margin
Steelers by 8
Luck in points
3.2 for the Steelers
Luck-adjusted margin
Steelers by 4.8
Replay with same day's form
Broncos 51% · Steelers 49% 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 5 2021 games · Broncos · Steelers

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