luckadjusted

Week 17 2023 · December 31, 2023

Steelers at Seahawks, Week 17 2023: who deserved to win?

The Steelers beat the Seahawks 30–23 and were the better team on the day: replayed with the same form, they win 6 of 10.

Before kickoff the Seahawks were 63% favorites. The biggest swing (Q2, 5:36 left): the Seahawks converted 3rd & 11, worth 11 points of win probability to the Seahawks.

Final

Pittsburgh Steelers 30
Seattle Seahawks 23

December 31, 2023 · Lumen Field · Closing line: Seahawks −4.5

Luck index +35 Steelers lucky · −35 Seahawks

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 6, Seahawks win 4.

  1. 1 PIT 34 SEA 13
  2. 2 PIT 28 SEA 13
  3. 3 PIT 14 SEA 3
  4. 4 PIT 24 SEA 16
  5. 5 PIT 22 SEA 17
  6. 6 PIT 15 SEA 13
  7. 7 PIT 24 SEA 27
  8. 8 PIT 13 SEA 20
  9. 9 PIT 16 SEA 27
  10. 10 PIT 9 SEA 27

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 65% of them, Seahawks 35%, counting the 2% still level after regulation as half each. The line is what actually happened: Steelers by 7.

Show as a table
Final margin in the replaysShare of replays
Steelers by 17+16.7%
Steelers by 9–1620.9%
Steelers by 1–825.8%
Level after regulation1.9%
Seahawks by 1–819.1%
Seahawks by 9–1611.2%
Seahawks by 17+4.5%

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 +0.5 points to the Steelers: the final margin was Steelers by 7, without the luck Steelers by 6.5. 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, 39 yds made · 90% expected
  • J. Myers, 43 yds made · 84% expected
  • J. Myers, 42 yds made · 85% expected
  • C. Boswell, 26 yds made · 99% expected
  • C. Boswell, 21 yds made · 100% expected
  • J. Myers, 24 yds made · 99% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Steelers 2 for 10 yards, Seahawks 4 for 25 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 4:11 Illegal Motion on the Steelers (Pat Freiermuth), 5 yards, wiping out the play · pre-snap +4% SEA +1.8 pts
Q2 8:26 False Start on the Seahawks (Colby Parkinson), 5 yards · pre-snap +5% PIT +0.7 pts
Q2 5:52 False Start on the Seahawks, 5 yards · pre-snap +3% PIT +0.6 pts
Q3 12:35 Offensive Holding on the Seahawks (D.K. Metcalf), 10 yards +3% PIT +0.6 pts
Q3 10:41 False Start on the Steelers (Connor Heyward), 5 yards · pre-snap +2% SEA +0.9 pts
Q4 3:18 False Start on the Seahawks, 5 yards · pre-snap +1% PIT +0.6 pts

Steelers penalties, every game · Seahawks penalties, every game · All teams, 2023

When it happened

Seahawks’ chance of winning

As low as 0% and as high as 71%. 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 Seahawks were ahead in it, below while the Steelers were.
#WhenWhat happenedWin probability forNext drive
1 Q1 11:40 The Steelers were stopped on 3rd & 53rd & 4th downs · 44% expected +6% SEA PIT: Turnover on downs
2 Q1 6:23 The Steelers converted 4th & 13rd & 4th downs · 75% expected +7% PIT PIT: Touchdown
3 Q2 11:09 The Steelers were stopped on 3rd & 83rd & 4th downs · 34% expected +7% SEA PIT: Field goal
4 Q2 5:36 The Seahawks converted 3rd & 113rd & 4th downs · 25% expected +11% SEA SEA: Touchdown
5 Q2 4:12 The Steelers converted 3rd & 43rd & 4th downs · 48% expected +9% PIT PIT: Touchdown
6 Q4 15:00 C. Parkinson dropped a catchable passDrops · 0 drops on 50 catchable balls before this +7% PIT SEA: Field goal
7 Q4 11:35 The Steelers converted 3rd & 63rd & 4th downs · 40% expected +10% PIT PIT: Field goal
8 Q4 7:07 The Seahawks fumbled and the Steelers recoveredFumble bounces · loose balls are close to 50/50 +6% PIT SEA: 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.

  • Jamal Adams (SEA SS), out (IR) · 0.7 pts
  • Jordyn Brooks (SEA LB), out · 0.5 pts
  • Phil Haynes (SEA G), out (IR) · 0.2 pts
  • Kenny Pickett (PIT QB), out, replaced by m.rudolph · 1.6 pts
  • Minkah Fitzpatrick (PIT FS), out · 0.9 pts
  • Elandon Roberts (PIT LB), out · 0.4 pts
  • Keanu Neal (PIT FS), out (IR) · 0.4 pts
  • Damontae Kazee (PIT SS), out (IR) · 0.3 pts
  • Trenton Thompson (PIT SS), 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

Steelers 81% · Seahawks 19%

Final margin
Steelers by 7
Luck in points
0.5 for the Steelers
Luck-adjusted margin
Steelers by 6.5
Replay with same day's form
Steelers 65% · Seahawks 35% 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; injuries from snap counts and injury reports.

Methodology and validation · All Week 17 2023 games · Steelers · Seahawks

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