luckadjusted

NFC Championship 2021 · January 30, 2022

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

49ers at Rams, NFC Championship 2021: who deserved to win?

The Rams beat the 49ers 20–17, but it was a coin flip: replayed with the way both teams played, the Rams win 6 of 10. Luck ran their way: judgment calls alone were worth 4.5 points to the Rams.

Before kickoff the Rams were 60% favorites. The biggest swing (Q4, 1:19 left): the 49ers were stopped on 3rd & 13, worth 18 points of win probability to the Rams.

Final

San Francisco 49ers 17
Los Angeles Rams 20

January 30, 2022 · SoFi Stadium · Closing line: Rams −3.5

Luck index +44 Rams lucky · −44 49ers

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 4, Rams win 6.

  1. 1 SF 27 LA 10
  2. 2 SF 13 LA 3
  3. 3 SF 26 LA 20
  4. 4 SF 23 LA 20
  5. 5 SF 19 LA 21
  6. 6 SF 17 LA 21
  7. 7 SF 21 LA 29
  8. 8 SF 24 LA 34
  9. 9 SF 17 LA 31
  10. 10 SF 7 LA 29

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 44% of them, Rams 56%, counting the 7% still level after regulation as half each. The line is what actually happened: Rams by 3.

Show as a table
Final margin in the replaysShare of replays
49ers by 17+7.0%
49ers by 9–1612.5%
49ers by 1–823.7%
Level after regulation6.5%
Rams by 1–824.4%
Rams by 9–1615.6%
Rams by 17+10.2%

Where the luck was

Take the luck out

The final margin was Rams by 3. Remove the luck, one kind at a time, and it becomes Rams by 0.3.

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.

  • M. Gay, 54 yds missed · 69% expected
  • R. Gould, 38 yds made · 90% expected
  • M. Gay, 40 yds made · 89% expected
  • M. Gay, 30 yds made · 97% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Rams’ chance of winning

As low as 17% 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 Rams were ahead in it, below while the 49ers were.
#WhenWhat happenedWin probability forNext drive
1 Q1 7:04 The Rams were stopped on 3rd & 33rd & 4th downs · 43% expected +17% SF LA: Touchdown
2 Q2 8:50 The Rams converted 3rd & 133rd & 4th downs · 23% expected +11% LA LA: Touchdown
3 Q3 8:03 The Rams were stopped on 4th & 13rd & 4th downs · 73% expected +9% SF LA: Touchdown
4 Q4 9:47 Unnecessary Roughness on the 49ers (Jimmie Ward), 15 yardsJudgment calls · 5 flags in 3356 snaps before, position avg 1 per 530 +9% LA LA: Field goal
5 Q4 8:50 The Rams converted 3rd & 103rd & 4th downs · 27% expected +14% LA LA: Field goal
6 Q4 7:34 The Rams were stopped on 3rd & 33rd & 4th downs · 51% expected +8% SF LA: Field goal
7 Q4 3:26 The Rams converted 3rd & 33rd & 4th downs · 51% expected +13% LA LA: Field goal
8 Q4 1:19 The 49ers were stopped on 3rd & 133rd & 4th downs · 23% expected +18% LA –

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.

  • Taylor Rapp (LA FS), out · 0.5 pts
  • Jordan Fuller (LA SS), out (IR) · 0.4 pts
  • Marcell Harris (SF LB), 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

49ers 55% · Rams 45%

Final margin
Rams by 3
Luck in points
2.7 for the Rams
Luck-adjusted margin
Rams by 0.3
Replay with same day's form
49ers 44% · Rams 56% 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 Conference championships 2021 games · 49ers · Rams

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