luckadjusted

Week 15 2019 · December 15, 2019

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

Bills at Steelers, Week 15 2019: who deserved to win?

The Bills beat the Steelers 17–10 and were the better team on the day: replayed with the same form, they win 7 of 10. The Steelers had the bounces: fumble bounces alone were worth 20 points of win probability to the Steelers.

Before kickoff it was a pick’em. The biggest swing (Q4, 8:00 left): the Bills converted 3rd & 9, worth 23 points of win probability to the Bills.

Final

Buffalo Bills 17
Pittsburgh Steelers 10

December 15, 2019 · Heinz Field · Closing line: Steelers −1

Luck index +27 Bills lucky · −27 Steelers

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. Bills win 7, Steelers win 3.

  1. 1 BUF 34 PIT 8
  2. 2 BUF 38 PIT 19
  3. 3 BUF 24 PIT 9
  4. 4 BUF 19 PIT 7
  5. 5 BUF 12 PIT 3
  6. 6 BUF 23 PIT 17
  7. 7 BUF 16 PIT 13
  8. 8 BUF 13 PIT 16
  9. 9 BUF 12 PIT 20
  10. 10 BUF 13 PIT 31

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

Bills win 73% of them, Steelers 27%, counting the 3% still level after regulation as half each. The line is what actually happened: Bills by 7.

Show as a table
Final margin in the replaysShare of replays
Bills by 17+25.6%
Bills by 9–1621.1%
Bills by 1–823.8%
Level after regulation3.0%
Steelers by 1–814.9%
Steelers by 9–167.5%
Steelers by 17+4.1%

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 +8.9 points to the Steelers: the final margin was Bills by 7, without the luck Bills by 15.9. 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.

  • C. Boswell, 49 yds made · 70% expected
  • S. Hauschka, 36 yds made · 90% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Bills 8 for 70 yards, Steelers 6 for 30 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 15:00 Offensive Holding on the Bills (Siran Neal), 10 yards +2% PIT +0.9 pts
Q1 13:01 Neutral Zone Infraction on the Steelers (T.J. Watt), 5 yards · pre-snap +2% BUF +0.4 pts
Q1 10:11 Illegal Motion on the Steelers, 5 yards, wiping out the play · pre-snap +3% BUF +1.4 pts
Q2 13:34 Defensive Offside on the Bills (Jordan Phillips), 5 yards · pre-snap +1% PIT +0.4 pts
Q2 6:33 Illegal Block Above the Waist on the Bills, 10 yards +3% PIT +0.9 pts
Q2 5:02 Defensive Offside on the Steelers (Bud Dupree), 5 yards, wiping out the play · pre-snap +5% BUF +1.0 pts
Q2 3:08 False Start on the Bills, 5 yards · pre-snap +2% PIT +0.3 pts
Q2 2:28 Face Mask on the Bills (Kevin Johnson), 10 yards +1% PIT +0.7 pts
Q3 6:48 Illegal Block Above the Waist on the Bills, 10 yards +4% PIT +0.9 pts
Q3 4:46 Encroachment on the Bills (Vincent Taylor), 5 yards · pre-snap +2% PIT +0.7 pts
Q4 10:20 False Start on the Steelers, 5 yards · pre-snap +4% BUF +0.5 pts
Q4 3:04 Delay of Game on the Steelers, 5 yards · pre-snap +4% BUF +0.7 pts
Q4 1:31 Face Mask on the Bills (Matt Milano), 15 yards +9% PIT +1.8 pts
Q4 1:01 False Start on the Steelers, 5 yards · pre-snap +3% BUF +0.6 pts

Bills penalties, every game · Steelers penalties, every game · All teams, 2019

When it happened

Steelers’ chance of winning

As low as 0% and as high as 77%. 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 Bills were.
#WhenWhat happenedWin probability forNext drive
1 Q1 1:55 The Bills converted 4th & 63rd & 4th downs · 32% expected +11% BUF BUF: Touchdown
2 Q3 14:53 The Steelers fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +9% PIT PIT: Touchdown
3 Q3 9:46 The Bills converted 3rd & 103rd & 4th downs · 23% expected +12% BUF BUF: Turnover
4 Q3 9:10 The Bills fumbled and the Steelers recoveredFumble bounces · loose balls are close to 50/50 +8% PIT BUF: Punt
5 Q4 8:00 The Bills converted 3rd & 93rd & 4th downs · 25% expected +23% BUF BUF: Touchdown
6 Q4 3:10 The Steelers converted 3rd & 13rd & 4th downs · 67% expected +13% PIT PIT: Turnover
7 Q4 2:00 The Steelers were stopped on 4th & 73rd & 4th downs · 27% expected +14% BUF PIT: Turnover
8 Q4 1:31 Face Mask on the Bills (Matt Milano), 15 yardsJudgment calls · 2 flags in 845 snaps before, position avg 1 per 393 +9% PIT PIT: 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.

  • JuJu Smith-Schuster (PIT WR), out · 0.7 pts
  • Vance McDonald (PIT TE), out · 0.5 pts
  • Duke Williams (BUF WR), out · 0.4 pts
  • Ty Nsekhe (BUF T), out · 0.4 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

Bills 100% · Steelers 0%

Final margin
Bills by 7
Luck in points
8.9 for the Steelers
Luck-adjusted margin
Bills by 15.9
Replay with same day's form
Bills 73% · Steelers 27% 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 15 2019 games · Bills · Steelers

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