Week 18 2021 · January 9, 2022
No FTN charting for this game (drops and interception-worthy throws are not modelled).
49ers at Rams, Week 18 2021: who deserved to win?
The 49ers beat the Rams 27–24 and were the better team on the day: replayed with the same form, they win 8 of 10. The Rams had the bounces: judgment calls alone were worth 6.7 points to the Rams.
An off day for the Rams: their defense played far below its usual level. In a fresh game against the 49ers they would win 58% of the time; with this day’s form, 25%. The numbers
Before kickoff the Rams were 59% favorites. The biggest swing (QOT, 2:48 left): R. Gould made 24-yard field goal, worth 55 points of win probability to the Rams.
Final (OT)
 San Francisco 49ers | 27 |
|---|---|
 Los Angeles Rams | 24 |
Replay with same day's form
Luck index +25 49ers about even · −25 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. 49ers win 8, Rams win 2.
- 1 SF 44 LA 16
- 2 SF 50 LA 29
- 3 SF 44 LA 28
- 4 SF 34 LA 22
- 5 SF 39 LA 29
- 6 SF 30 LA 23
- 7 SF 27 LA 23
- 8 SF 35 LA 33
- 9 SF 20 LA 23
- 10 SF 13 LA 27
Three other ways to ask
Each answers a different question, so none of them replaces the replay above.
Before kickoff
The closing betting line, turned into a probability. What everyone knew before the game.
Same teams, fresh 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.
Only coin-flips re-rolled
Every kick, fumble bounce, drop, conversion and judgment call redrawn; everything else fixed. The narrowest view of luck.
An off day for the Rams
Their defense played far below its usual level. In a fresh game against the 49ers they would win 58% of the time; with this day’s form, 25%.
Same teams, fresh game
Replay with same day's form
33 points apart for the Rams: the gap is how differently this game went from what the two teams usually are.
| Unit | This game | Usual level | Better or worse than usual |
|---|---|---|---|
| 49ers offenseEPA per play gained | +0.23 | +0.17 | better by 0.06 |
| 49ers defenseEPA per play allowed | +0.11 | +0.07 | worse by 0.04 |
| Rams offenseEPA per play gained | +0.11 | +0.15 | worse by 0.04 |
| Rams defenseEPA per play allowed | +0.23 | +0.05 | worse by 0.17 |
EPA (expected points added) per play on competitive snaps, turnovers left out because they are valued as luck. Usual level: the team’s earlier games this season plus half of last season, pulled toward the league average. One team’s defense and the other team’s offense are the same snaps, so one game can’t fully say whose day it was; it shows how far this one was from both teams’ norms.
How 4,000 replays ended
49ers win 75% of them, Rams 25%, counting the 4% still level after regulation as half each. The line is what actually happened: 49ers by 3.
Show as a table
| Final margin in the replays | Share of replays |
|---|---|
| 49ers by 17+ | 24.9% |
| 49ers by 9–16 | 21.0% |
| 49ers by 1–8 | 26.2% |
| Level after regulation | 4.1% |
| Rams by 1–8 | 13.5% |
| Rams by 9–16 | 7.0% |
| Rams by 17+ | 3.3% |
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 49ers by 10.5.
The kicks
How likely each kicker was to make that kick (his own record, the distance and the weather), and what happened.
- M. Gay, 43 yds made · 85% expected
- R. Gould, 42 yds made · 86% expected
- R. Gould, 24 yds made · 98% expected
When it happened
Rams’ chance of winning
As low as 0% and as high as 99%. Numbers mark the biggest luck moments, listed below.
| # | When | What happened | Win probability for | Next drive |
|---|---|---|---|---|
| 1 | Q1 11:12 | The Rams converted 3rd & 93rd & 4th downs · 26% expected | +15% LA | LA: Field goal |
| 2 | Q4 5:36 | The Rams converted 3rd & 63rd & 4th downs · 33% expected | +13% LA | LA: Touchdown |
| 3 | Q4 2:34 | The Rams converted 3rd & 43rd & 4th downs · 34% expected | +16% LA | LA: Touchdown |
| 4 | QOT 8:33 | Offensive Holding on the 49ers, 10 yards, wiping out the playJudgment calls | +18% LA | LA: Turnover |
| 5 | QOT 7:29 | The 49ers converted 3rd & 63rd & 4th downs · 36% expected | +35% SF | SF: Field goal |
| 6 | QOT 2:57 | The 49ers were stopped on 3rd & 73rd & 4th downs · 26% expected | +18% SF | SF: Field goal |
| 7 | QOT 2:48 | R. Gould made 24-yard field goalKicks · 98% expected for him | +55% LA | – |
| 8 | QOT 2:31 | Defensive Pass Interference on the 49ers, 7 yardsJudgment calls | +10% LA | LA: Turnover |
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.
- Ernest Jones (LA LB), out (IR) · 0.5 pts
- Darrell Henderson (LA RB), out (IR) · 0.2 pts
- Trent Williams (SF T), out · 1.2 pts
- K'Waun Williams (SF CB), out · 0.5 pts
- Azeez Al-Shaair (SF LB), 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 98% · Rams 2%
- Final margin
- 49ers by 3
- Luck in points
- 7.5 for the Rams
- Luck-adjusted margin
- 49ers by 10.5
- Replay with same day's form
- 49ers 75% · Rams 25% unchanged: why
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 18 2021 games · 
49ers · 
Rams
More from Week 18 2021
- Chiefs at Broncos KC 28–24 · replay 79% for the winner
- Cowboys at Eagles DAL 51–26 · replay 94% for the winner
- Bears at Vikings MIN 31–17 · replay 54% for the winner
- Bengals at Browns CLE 21–16 · replay 89% for the winner
- Packers at Lions DET 37–30 · replay 53% for the winner
- Colts at Jaguars JAX 26–11 · replay 82% for the winner
- Steelers at Ravens PIT 16–13 · replay 17% for the winner
- Titans at Texans TEN 28–25 · replay 71% for the winner
- Washington at Giants WAS 22–7 · replay 92% for the winner
- Panthers at Buccaneers TB 41–17 · replay 99% for the winner
- Patriots at Dolphins MIA 33–24 · replay 28% for the winner
- Saints at Falcons NO 30–20 · replay 77% for the winner
- Jets at Bills BUF 27–10 · replay 100% for the winner
- Seahawks at Cardinals SEA 38–30 · replay 83% for the winner
- Chargers at Raiders LV 35–32 · replay 58% for the winner