luckadjusted

Divisional round 2023 · January 20, 2024

Packers at 49ers, Divisional round 2023: who deserved to win?

The 49ers beat the Packers 24–21 and were the better team on the day: replayed with the same form, they win 7 of 10. The Packers had the bounces: judgment calls alone were worth 26 points of win probability to the Packers.

Before kickoff the 49ers were 78% favorites. The game turned on a luck play (Q4, 6:21 left): A. Carlson missed 41-yard field goal, worth 16 points of win probability to the 49ers. The biggest single swing (Q3, 9:40 left): Defensive Pass Interference on the 49ers (Ambry Thomas), 41 yards.

Final

Green Bay Packers 21
San Francisco 49ers 24

January 20, 2024 · Levi's Stadium · Closing line: 49ers −10.5

Luck index +29 49ers lucky · −29 Packers

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. Packers win 3, 49ers win 7.

  1. 1 GB 22 SF 7
  2. 2 GB 27 SF 20
  3. 3 GB 17 SF 14
  4. 4 GB 24 SF 26
  5. 5 GB 17 SF 22
  6. 6 GB 17 SF 24
  7. 7 GB 13 SF 23
  8. 8 GB 10 SF 24
  9. 9 GB 13 SF 33
  10. 10 GB 7 SF 33

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

Packers win 29% of them, 49ers 71%, counting the 5% still level after regulation as half each. The line is what actually happened: 49ers by 3.

Show as a table
Final margin in the replaysShare of replays
Packers by 17+3.8%
Packers by 9–167.0%
Packers by 1–815.1%
Level after regulation4.5%
49ers by 1–825.0%
49ers by 9–1621.1%
49ers by 17+23.4%

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 +6.4 points to the Packers: the final margin was 49ers by 3, without the luck 49ers by 9.4. 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.

  • A. Carlson, 29 yds made · 96% expected
  • A. Carlson, 29 yds made · 96% expected
  • J. Moody, 48 yds blocked · 74% expected
  • J. Moody, 52 yds made · 66% expected
  • A. Carlson, 41 yds missed · 85% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Packers 1 for 5 yards, 49ers 6 for 83 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 9:00 Defensive Pass Interference on the 49ers (Ambry Thomas), 13 yards +5% GB +1.7 pts
Q1 6:00 False Start on the 49ers, 5 yards · pre-snap +1% GB +0.6 pts
Q1 4:05 Defensive Pass Interference on the 49ers, 7 yards +3% GB +1.2 pts
Q1 2:03 Ineligible Downfield Pass on the Packers, 5 yards +1% SF +0.7 pts
Q3 9:40 Defensive Pass Interference on the 49ers (Ambry Thomas), 41 yards +18% GB +4.4 pts
Q3 5:23 Unnecessary Roughness on the 49ers, 12 yards +1% GB +1.1 pts
Q4 8:50 Neutral Zone Infraction on the 49ers (Arik Armstead), 5 yards · pre-snap 0% GB +0.5 pts

Packers penalties, every game · 49ers penalties, every game · All teams, 2023

When it happened

49ers’ chance of winning

As low as 16% 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 49ers were ahead in it, below while the Packers were.
#WhenWhat happenedWin probability forNext drive
1 Q2 8:48 The 49ers converted 3rd & 53rd & 4th downs · 43% expected +12% SF SF: Touchdown
2 Q2 0:10 J. Moody had a 48-yard field goal blockedKicks · 74% expected for him, 3 of 4 from 45+ before +14% GB SF: Punt
3 Q3 9:40 Defensive Pass Interference on the 49ers (Ambry Thomas), 41 yardsJudgment calls · 7 flags in 1357 snaps before, position avg 1 per 216 +18% GB GB: Touchdown
4 Q3 2:18 The Packers were stopped on 3rd & 113rd & 4th downs · 27% expectedThe Packers threw an interception-worthy pass, and it was pickedInterceptions · 50% expected to stay out of the defense's hands +13% SF GB: Punt
5 Q4 11:23 The 49ers converted 3rd & 103rd & 4th downs · 29% expected +13% SF SF: Punt
6 Q4 6:21 The game turned hereA. Carlson missed 41-yard field goalKicks · 85% expected for him +16% SF GB: Turnover
7 Q4 3:38 The 49ers converted 3rd & 53rd & 4th downs · 43% expected +12% SF SF: Touchdown
8 Q4 0:52 The Packers threw an interception-worthy pass, and it was pickedInterceptions · 50% expected to stay out of the defense's hands +14% SF –

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.

  • Eric Stokes (GB CB), out (IR) · 0.4 pts
  • AJ Dillon (GB RB), out · 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

Packers 6% · 49ers 94%

Final margin
49ers by 3
Luck in points
6.4 for the Packers
Luck-adjusted margin
49ers by 9.4
Replay with same day's form
Packers 29% · 49ers 71% 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 Divisional round 2023 games · Packers · 49ers

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