luckadjusted

Week 12 2023 · November 23, 2023

49ers at Seahawks, Week 12 2023: who deserved to win?

The 49ers beat the Seahawks 31–13, and it was no fluke: replayed with the way both teams actually played, the 49ers win 10 of 10.

Before kickoff the 49ers were 70% favorites.

Final

San Francisco 49ers 31
Seattle Seahawks 13

November 23, 2023 · Lumen Field · Closing line: 49ers −7

Luck index +2 49ers about even · −2 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. 49ers win 10, Seahawks win 0.

  1. 1 SF 48 SEA 7
  2. 2 SF 41 SEA 10
  3. 3 SF 37 SEA 10
  4. 4 SF 23 SEA 0
  5. 5 SF 34 SEA 14
  6. 6 SF 34 SEA 17
  7. 7 SF 30 SEA 16
  8. 8 SF 31 SEA 20
  9. 9 SF 23 SEA 16
  10. 10 SF 23 SEA 20

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

49ers win 98% of them, Seahawks 2%. The line is what actually happened: 49ers by 18.

Show as a table
Final margin in the replaysShare of replays
49ers by 17+82.2%
49ers by 9–1613.1%
49ers by 1–83.0%
Level after regulation0.3%
Seahawks by 1–81.1%
Seahawks by 9–160.3%
Seahawks by 17+0.0%

Where the luck was

Take the luck out

The final margin was 49ers by 18. Remove the luck, one kind at a time, and it becomes 49ers by 7.1.

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.

  • J. Myers, 51 yds made · 68% expected
  • J. Moody, 32 yds made · 94% expected
  • J. Myers, 53 yds missed · 65% expected
  • J. Myers, 30 yds made · 96% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Seahawks’ chance of winning

As low as 0% and as high as 57%. 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 49ers were.
#WhenWhat happenedWin probability forNext drive
1 Q1 9:11 J. Myers made 51-yard field goalKicks · 68% expected for him, 32 of 44 from 45+ before +5% SEA SEA: Punt
2 Q1 5:46 The 49ers were stopped on 3rd & 143rd & 4th downs · 24% expected +5% SEA SF: Punt
3 Q1 1:36 The 49ers converted 3rd & 73rd & 4th downs · 36% expected +4% SF SF: Touchdown
4 Q3 11:30 The 49ers were intercepted on a well-placed throwInterceptions · 0% expected to stay out of the defense's handsReturn touchdown by the SeahawksSpecial teams +7% SEA SF: Punt
5 Q3 9:15 The Seahawks converted 3rd & 93rd & 4th downs · 26% expected +8% SEA SEA: Field goal
6 Q3 4:01 The Seahawks were stopped on 3rd & 73rd & 4th downs · 23% expected +4% SF SEA: Field goal
7 Q4 13:53 Illegal Shift on the Seahawks (Zach Charbonnet), 5 yards, wiping out the playPre-snap flags · 0 flags in 336 snaps before, position avg 1 per 870 +5% SF SF: Touchdown
8 Q4 12:10 The Seahawks were stopped on 3rd & 83rd & 4th downs · 28% expected +5% SF SEA: Punt

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.

  • Uchenna Nwosu (SEA LB), out (IR) · 0.2 pts
  • Talanoa Hufanga (SF SS), out (IR) · 0.6 pts
  • Spencer Burford (SF G), 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

49ers 89% · Seahawks 11%

Final margin
49ers by 18
Luck in points
10.9 for the 49ers
Luck-adjusted margin
49ers by 7.1
Replay with same day's form
49ers 98% · Seahawks 2% 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 12 2023 games · 49ers · Seahawks

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