luckadjusted

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 it was a coin flip: replayed with the way both teams played, the Steelers win 5 of 10. Luck ran their way: judgment calls alone were worth 3.7 points to the Steelers.

Before kickoff the Broncos were 56% favorites. The biggest swing (Q1, 12:09 left): the Steelers converted 3rd & 7, worth 16 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 +48 Steelers lucky · −48 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 30 PIT 17
  3. 3 DEN 21 PIT 14
  4. 4 DEN 7 PIT 3
  5. 5 DEN 10 PIT 8
  6. 6 DEN 24 PIT 26
  7. 7 DEN 20 PIT 24
  8. 8 DEN 20 PIT 27
  9. 9 DEN 21 PIT 34
  10. 10 DEN 0 PIT 22

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 48% of them, Steelers 52%, 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+9.1%
Broncos by 9–1613.2%
Broncos by 1–822.8%
Level after regulation7.3%
Steelers by 1–823.5%
Steelers by 9–1614.8%
Steelers by 17+9.3%

Where the luck was

Take the luck out

The final margin was Steelers by 8. Remove the luck, one kind at a time, and it becomes Steelers by 1.5.

Each row takes one kind of luck out of the margin. Color shows which team it helped. Luck shares are the fitted ones (how much of each component 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 · 89% expected
  • C. Boswell, 48 yds made · 77% expected
  • B. McManus, 29 yds made · 97% expected
  • C. Boswell, 43 yds made · 83% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

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 · 34% expected +16% 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 48-yard field goalKicks · 77% expected for him, 13 of 15 from 45+ before +7% PIT PIT: Punt
4 Q2 8:42 The Broncos converted 3rd & 13rd & 4th downs · 73% expected +12% DEN DEN: Field goal
5 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
6 Q4 1:03 The Broncos converted 3rd & 53rd & 4th downs · 41% expected +7% DEN DEN: Turnover
7 Q4 0:22 The Broncos were stopped on 3rd & 33rd & 4th downs · 43% expected +5% PIT DEN: Turnover
8 Q4 0:17 The Broncos were stopped on 4th & 33rd & 4th downs · 43% expected +7% PIT DEN: 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.

  • 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 36% · Steelers 64%

Final margin
Steelers by 8
Luck in points
6.5 for the Steelers
Luck-adjusted margin
Steelers by 1.5
Replay with same day's form
Broncos 48% · Steelers 52% 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 5 2021 games · Broncos · Steelers

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