luckadjusted

Week 14 2020 · December 13, 2020

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

Steelers at Bills, Week 14 2020: who deserved to win?

The Bills beat the Steelers 26–15 and were the better team on the day: replayed with the same form, they win 8 of 10. The Steelers had the bounces: judgment calls alone were worth 10 points of win probability to the Steelers.

Before kickoff the Bills were 56% favorites. The biggest swing (Q2, 1:02 left): Return touchdown by the Bills, worth 27 points of win probability to the Bills.

Final

Pittsburgh Steelers 15
Buffalo Bills 26

December 13, 2020 · New Era Field · Closing line: Bills −2

Luck index +24 Bills about even · −24 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. Steelers win 2, Bills win 8.

  1. 1 PIT 41 BUF 26
  2. 2 PIT 23 BUF 20
  3. 3 PIT 38 BUF 40
  4. 4 PIT 9 BUF 13
  5. 5 PIT 19 BUF 27
  6. 6 PIT 27 BUF 38
  7. 7 PIT 16 BUF 30
  8. 8 PIT 16 BUF 34
  9. 9 PIT 16 BUF 39
  10. 10 PIT 3 BUF 34

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

Steelers win 24% of them, Bills 76%, counting the 4% still level after regulation as half each. The line is what actually happened: Bills by 11.

Show as a table
Final margin in the replaysShare of replays
Steelers by 17+3.9%
Steelers by 9–166.3%
Steelers by 1–813.8%
Level after regulation3.9%
Bills by 1–824.4%
Bills by 9–1620.3%
Bills by 17+27.4%

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 +1.7 points to the Steelers: the final margin was Bills by 11, without the luck Bills by 12.7. 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.

  • T. Bass, 34 yds made · 91% expected
  • T. Bass, 23 yds made · 98% expected
  • Extra point missed · 93% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Steelers 3 for 55 yards, Bills 7 for 48 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 14:10 Offensive Holding on the Bills (Andre Smith), 10 yards +2% PIT +1.1 pts
Q1 13:28 False Start on the Bills, 5 yards · pre-snap +2% PIT +0.7 pts
Q1 1:08 Defensive Too Many Men on Field on the Steelers, 5 yards · pre-snap +1% BUF +1.0 pts
Q2 14:34 Neutral Zone Infraction on the Bills (Tre'Davious White), 5 yards · pre-snap +1% PIT +0.6 pts
Q2 2:10 Roughing the Passer on the Steelers, 15 yards, wiping out the play +5% PIT +0.5 pts
Q2 1:02 Neutral Zone Infraction on the Bills, 5 yards · pre-snap +1% PIT +0.5 pts
Q3 9:18 Illegal Block Above the Waist on the Bills (Josh Norman), 10 yards +2% PIT +0.9 pts
Q4 12:33 Defensive Holding on the Bills (Matt Milano), 3 yards 0% PIT +0.7 pts
Q4 9:08 Defensive Pass Interference on the Steelers, 35 yards +3% BUF +3.8 pts
Q4 7:11 Offensive Holding on the Bills, 10 yards, wiping out the play +3% PIT +3.7 pts

Steelers penalties, every game · Bills penalties, every game · All teams, 2020

When it happened

Bills’ chance of winning

As low as 31% and as high as 100%. 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 Bills were ahead in it, below while the Steelers were.
#WhenWhat happenedWin probability forNext drive
1 Q1 5:33 The Steelers converted 3rd & 63rd & 4th downs · 35% expected +5% PIT PIT: Punt
2 Q1 2:28 The Steelers were stopped on 3rd & 63rd & 4th downs · 36% expected +5% BUF PIT: Punt
3 Q2 9:42 The Bills fumbled and the Steelers recoveredFumble bounces · loose balls are close to 50/50 +6% PIT BUF: Punt
4 Q2 9:36 The Steelers fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +8% PIT PIT: Touchdown
5 Q2 8:14 The Bills fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +5% BUF BUF: Punt
6 Q2 4:14 The Bills converted 3rd & 33rd & 4th downs · 51% expected +5% BUF BUF: Field goal
7 Q2 2:10 Roughing the Passer on the Steelers, 15 yards, wiping out the playJudgment calls +5% PIT BUF: Field goal
8 Q2 1:02 Neutral Zone Infraction on the Bills, 5 yardsPre-snap flagsReturn touchdown by the BillsSpecial teams +27% BUF PIT: Opp touchdown

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.

  • John Brown (BUF WR), out (IR) · 0.6 pts
  • Cody Ford (BUF T), out (IR) · 0.5 pts
  • Cameron Lewis (BUF DB), out (IR) · 0.3 pts
  • Tyler Kroft (BUF TE), out · 0.2 pts
  • Joe Haden (PIT CB), out · 1.1 pts
  • Vince Williams (PIT LB), out (IR) · 0.3 pts
  • Bud Dupree (PIT LB), out (IR) · 0.3 pts
  • Robert Spillane (PIT LB), 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

Steelers 2% · Bills 98%

Final margin
Bills by 11
Luck in points
1.7 for the Steelers
Luck-adjusted margin
Bills by 12.7
Replay with same day's form
Steelers 24% · Bills 76% 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 14 2020 games · Steelers · Bills

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