luckadjusted

NFC Championship 2023 · January 28, 2024

Lions at 49ers, NFC Championship 2023: who deserved to win?

The 49ers beat the Lions 34–31 and were the better team on the day: replayed with the same form, they win 6 of 10. The Lions had the bounces: kicks alone were worth 2.4 points to the Lions.

Before kickoff the 49ers were 71% favorites. The biggest swing (Q4, 7:38 left): the Lions were stopped on 4th & 3, worth 16 points of win probability to the 49ers.

Final

Detroit Lions 31
San Francisco 49ers 34

January 28, 2024 · Levi's Stadium · Closing line: 49ers −7.5

Luck index +40 49ers lucky · −40 Lions

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. Lions win 4, 49ers win 6.

  1. 1 DET 36 SF 14
  2. 2 DET 26 SF 14
  3. 3 DET 30 SF 24
  4. 4 DET 20 SF 17
  5. 5 DET 28 SF 31
  6. 6 DET 23 SF 27
  7. 7 DET 28 SF 36
  8. 8 DET 9 SF 21
  9. 9 DET 6 SF 22
  10. 10 DET 20 SF 44

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

Lions win 40% of them, 49ers 60%, counting the 3% 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
Lions by 17+7.5%
Lions by 9–1612.3%
Lions by 1–819.3%
Level after regulation2.5%
49ers by 1–825.2%
49ers by 9–1616.0%
49ers by 17+17.2%

Where the luck was

Take the luck out

The final margin was 49ers by 3. Remove the luck, one kind at a time, and it becomes Lions by 1.8.

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. Moody, 48 yds missed · 75% expected
  • M. Badgley, 21 yds made · 98% expected
  • J. Moody, 43 yds made · 83% expected
  • J. Moody, 33 yds made · 94% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

49ers’ chance of winning

As low as 7% 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 Lions were.
#WhenWhat happenedWin probability forNext drive
1 Q1 7:58 J. Moody missed 48-yard field goalKicks · 75% expected for him, 4 of 6 from 45+ before +9% DET SF: Touchdown
2 Q2 0:10 M. Badgley made 21-yard field goalKicks · 98% expected for him +9% SF DET: Turnover on downs
3 Q3 7:03 The Lions were stopped on 4th & 23rd & 4th downs · 62% expectedJ. Reynolds dropped a catchable passDrops · 3 drops on 99 catchable balls before this +6% SF DET: Turnover
4 Q3 5:15 The Lions fumbled and the 49ers recoveredFumble bounces · loose balls are close to 50/50 +9% SF DET: Punt
5 Q3 2:23 S. LaPorta dropped a catchable passDrops · 5 drops on 114 catchable balls before this +8% SF DET: Punt
6 Q3 2:17 The Lions were stopped on 3rd & 93rd & 4th downs · 31% expectedJ. Reynolds dropped a catchable passDrops · 4 drops on 100 catchable balls before this +9% SF DET: Punt
7 Q4 9:56 J. Moody made 33-yard field goalKicks · 94% expected for him +9% SF SF: Touchdown
8 Q4 7:38 The Lions were stopped on 4th & 33rd & 4th downs · 53% expected +16% SF DET: 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.

  • Jonah Jackson (DET G), out · 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

Lions 59% · 49ers 41%

Final margin
49ers by 3
Luck in points
4.8 for the 49ers
Luck-adjusted margin
Lions by 1.8
Replay with same day's form
Lions 40% · 49ers 60% 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 Conference championships 2023 games · Lions · 49ers

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