luckadjusted

Week 1 2021 · September 12, 2021

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

Seahawks at Colts, Week 1 2021: who deserved to win?

The Seahawks beat the Colts 28–16 and were the better team on the day: replayed with the same form, they win 6 of 10.

Before kickoff the Seahawks were 59% favorites. The biggest swing (Q1, 2:42 left): the Seahawks converted 3rd & 1, worth 13 points of win probability to the Seahawks.

Final

Seattle Seahawks 28
Indianapolis Colts 16

September 12, 2021 · Lucas Oil Stadium · Closing line: Seahawks −3

Luck index +38 Seahawks lucky · −38 Colts

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. Seahawks win 6, Colts win 4.

  1. 1 SEA 30 IND 6
  2. 2 SEA 31 IND 16
  3. 3 SEA 34 IND 24
  4. 4 SEA 19 IND 12
  5. 5 SEA 20 IND 17
  6. 6 SEA 17 IND 16
  7. 7 SEA 34 IND 37
  8. 8 SEA 35 IND 42
  9. 9 SEA 9 IND 20
  10. 10 SEA 23 IND 43

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

Seahawks win 62% of them, Colts 38%, counting the 3% still level after regulation as half each. The line is what actually happened: Seahawks by 12.

Show as a table
Final margin in the replaysShare of replays
Seahawks by 17+14.8%
Seahawks by 9–1617.4%
Seahawks by 1–826.6%
Level after regulation2.9%
Colts by 1–819.3%
Colts by 9–1612.2%
Colts by 17+6.8%

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 +6.9 points to the Seahawks: the final margin was Seahawks by 12, without the luck Seahawks by 5.1. Luck shares are the fitted ones (how much of each kind is luck).

Penalties: Seahawks 7 for 53 yards, Colts 2 for 16 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 14:20 Defensive Offside on the Seahawks (Jamal Adams), 5 yards, wiping out the play · pre-snap +5% IND +1.1 pts
Q1 4:24 False Start on the Seahawks (D.K. Metcalf), 5 yards · pre-snap +2% IND +0.8 pts
Q2 11:27 Taunting on the Seahawks (D.K. Metcalf), 15 yards +3% IND +1.4 pts
Q2 5:18 Ineligible Downfield Kick on the Seahawks (Darrell Taylor), 5 yards +1% IND +0.5 pts
Q2 3:41 Ineligible Downfield Pass on the Colts, 6 yards, wiping out the play +7% SEA +2.1 pts
Q2 1:31 Illegal Formation on the Seahawks, 5 yards, wiping out the play · pre-snap +8% IND +2.5 pts
Q3 0:02 Encroachment on the Seahawks, 5 yards · pre-snap +2% IND +0.7 pts
Q4 4:57 Defensive Pass Interference on the Seahawks (D.J. Reed), 13 yards 0% IND +1.4 pts
Q4 2:16 Offensive Holding on the Colts (Zach Pascal), 10 yards, wiping out the play +1% SEA +2.7 pts

Seahawks penalties, every game · Colts penalties, every game · All teams, 2021

When it happened

Colts’ chance of winning

As low as 0% and as high as 68%. 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 Colts were ahead in it, below while the Seahawks were.
#WhenWhat happenedWin probability forNext drive
1 Q1 4:11 The Seahawks converted 3rd & 93rd & 4th downs · 31% expected +6% SEA SEA: Touchdown
2 Q1 2:42 The Seahawks converted 3rd & 13rd & 4th downs · 75% expected +13% SEA SEA: Touchdown
3 Q1 1:31 The Seahawks converted 3rd & 63rd & 4th downs · 39% expected +9% SEA SEA: Touchdown
4 Q1 0:01 The Colts were stopped on 3rd & 53rd & 4th downs · 42% expected +7% SEA IND: Punt
5 Q2 3:41 Ineligible Downfield Pass on the Colts, 6 yards, wiping out the playJudgment calls +7% SEA SEA: Touchdown
6 Q2 1:31 Illegal Formation on the Seahawks, 5 yards, wiping out the playPre-snap flags +8% IND IND: Turnover on downs
7 Q3 5:42 The Seahawks fumbled and the Colts recoveredFumble bounces · loose balls are close to 50/50 +6% IND SEA: Punt
8 Q4 10:00 The Colts were stopped on 4th & 23rd & 4th downs · 60% expected +7% SEA IND: 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.

  • Xavier Rhodes (IND CB), out · 1.0 pts
  • T.Y. Hilton (IND WR), out (IR) · 0.9 pts
  • Cedric Ogbuehi (SEA T), out (IR) · 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

Seahawks 90% · Colts 10%

Final margin
Seahawks by 12
Luck in points
6.9 for the Seahawks
Luck-adjusted margin
Seahawks by 5.1
Replay with same day's form
Seahawks 62% · Colts 38% 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 1 2021 games · Seahawks · Colts

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