luckadjusted
NFL Week 9 · 2026

Week 16 2019 · December 21, 2019

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

Rams at 49ers, Week 16 2019: who deserved to win?

The 49ers beat the Rams 34–31, and the replays lean their way: with the same day's form, they win 6 of 10.

Before kickoff the 49ers were 70% favorites. The biggest swing (Q2, 0:56 left): Return touchdown by the 49ers, worth 31 points of win probability to the 49ers.

Final

Los Angeles Rams 31
San Francisco 49ers 34

December 21, 2019 · Levi's Stadium · Closing line: 49ers −7

Luck index +37 49ers lucky · −37 Rams

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. Rams win 4, 49ers win 6.

  1. 1 LA 34 SF 13
  2. 2 LA 40 SF 27
  3. 3 LA 29 SF 23
  4. 4 LA 36 SF 34
  5. 5 LA 34 SF 37
  6. 6 LA 25 SF 31
  7. 7 LA 35 SF 44
  8. 8 LA 28 SF 41
  9. 9 LA 10 SF 27
  10. 10 LA 17 SF 40

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

Rams win 37% of them, 49ers 63%, 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
Rams by 17+7.0%
Rams by 9–1610.9%
Rams by 1–817.4%
Level after regulation2.9%
49ers by 1–823.8%
49ers by 9–1618.6%
49ers by 17+19.6%

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 +3.2 points to the 49ers: the final margin was 49ers by 3, without the luck Rams by 0.2. 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.

  • R. Gould, 26 yds made · 96% expected
  • G. Zuerlein, 52 yds missed · 64% expected
  • G. Zuerlein, 52 yds made · 63% expected
  • R. Gould, 33 yds made · 92% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Rams 7 for 43 yards, 49ers 3 for 26 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 half toward luck; pre-snap fouls, which repeat, don’t count. How calls are valued

WhenFlagWin probability for
Q1 3:11 False Start on the Rams, 5 yards · pre-snap +1% SF +0.7 pts
Q1 0:06 Unnecessary Roughness on the 49ers (Marcell Harris), 6 yards +2% LA +0.9 pts
Q2 13:57 Defensive Too Many Men on Field on the Rams, 6 yards · pre-snap +1% SF +0.4 pts
Q3 14:56 False Start on the 49ers, 5 yards · pre-snap +1% LA +0.9 pts
Q3 14:01 Intentional Grounding on the Rams (Jared Goff), 10 yards +4% SF +0.9 pts
Q3 10:25 Offensive Holding on the Rams (Aaron Donald), 3 yards +1% SF +0.3 pts
Q3 7:57 Fair Catch Interference on the 49ers (D.J. Reed), 15 yards +5% LA +1.1 pts
Q3 5:50 False Start on the Rams, 5 yards · pre-snap +4% SF +0.8 pts
Q4 9:25 Delay of Game on the Rams, 5 yards · pre-snap +4% SF +0.6 pts
Q4 7:23 Unnecessary Roughness on the Rams (Eric Weddle), 9 yards +8% SF +1.2 pts

Rams penalties, every game · 49ers penalties, every game · All teams, 2019

When it happened

49ers’ chance of winning

As low as 21% 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 Rams were.
#WhenWhat happenedWin probability forNext drive
1 Q1 3:11 The Rams converted 3rd & 123rd & 4th downs · 24% expectedFalse Start on the Rams, 5 yardsPre-snap flags +8% LA LA: Touchdown
2 Q2 0:56 Return touchdown by the 49ersSpecial teams +31% SF SF: Opp touchdown
3 Q3 6:13 The Rams converted 3rd & 53rd & 4th downs · 40% expected +9% LA LA: Touchdown
4 Q3 5:12 The Rams converted 3rd & 63rd & 4th downs · 37% expected +9% LA LA: Touchdown
5 Q4 4:41 The Rams converted 3rd & 83rd & 4th downs · 31% expected +9% LA LA: Field goal
6 Q4 2:36 G. Zuerlein made a 52-yard field goalKicks · 63% expected for him, 7 of 10 from 45+ before +8% LA –
7 Q4 1:57 The 49ers converted 3rd & 163rd & 4th downs · 22% expected +14% SF SF: Field goal
8 Q4 0:58 The 49ers converted 3rd & 163rd & 4th downs · 22% expected +21% SF SF: Field goal

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.

  • Weston Richburg (SF C), out (IR) · 0.6 pts
  • Jaquiski Tartt (SF SS), out · 0.4 pts
  • Kwon Alexander (SF LB), out (IR) · 0.3 pts
  • Rob Havenstein (LA T), out · 1.0 pts
  • Troy Hill (LA CB), out · 0.6 pts
  • Brian Allen (LA C), out (IR) · 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

Rams 50% · 49ers 50%

Final margin
49ers by 3
Luck in points
3.2 for the 49ers
Luck-adjusted margin
Rams by 0.2
Replay with same day's form
Rams 37% · 49ers 63% unchanged: why
How much of each is luck?

0% treats it as skill, 100% as pure luck. The tick is our fit.

What counts

None by default: our tests measured no carryover after a lucky break. Slide it up to count a break for more than its own swing. 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 16 2019 games · Rams · 49ers

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