luckadjusted

Week 13 2021 · December 5, 2021

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

Jaguars at Rams, Week 13 2021: who deserved to win?

The Rams beat the Jaguars 37–7, and it was no fluke: replayed with the way both teams actually played, the Rams win 10 of 10. The Jaguars had the bounces: judgment calls alone were worth 9 points of win probability to the Jaguars.

Before kickoff the Rams were 85% favorites.

Final

Jacksonville Jaguars 7
Los Angeles Rams 37

December 5, 2021 · SoFi Stadium · Closing line: Rams −14

Luck index +3 Rams about even · −3 Jaguars

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. Jaguars win 0, Rams win 10.

  1. 1 JAX 20 LA 23
  2. 2 JAX 13 LA 20
  3. 3 JAX 14 LA 24
  4. 4 JAX 10 LA 23
  5. 5 JAX 21 LA 37
  6. 6 JAX 10 LA 30
  7. 7 JAX 6 LA 28
  8. 8 JAX 7 LA 34
  9. 9 JAX 6 LA 37
  10. 10 JAX 17 LA 52

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

Jaguars win 3% of them, Rams 97%, counting the 1% still level after regulation as half each. The line is what actually happened: Rams by 30.

Show as a table
Final margin in the replaysShare of replays
Jaguars by 17+0.1%
Jaguars by 9–160.4%
Jaguars by 1–81.9%
Level after regulation1.0%
Rams by 1–85.9%
Rams by 9–1617.3%
Rams by 17+73.4%

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 +0.5 points to the Jaguars: the final margin was Rams by 30, without the luck Rams by 30.5. 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.

  • M. Gay, 40 yds made · 89% expected
  • M. Gay, 44 yds made · 84% expected
  • M. Gay, 37 yds made · 92% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Jaguars 3 for 39 yards, Rams 7 for 47 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 11:46 Ineligible Downfield Pass on the Rams, 5 yards, wiping out the play +2% JAX +1.4 pts
Q2 14:15 Taunting on the Rams (Jalen Ramsey), 10 yards 0% JAX +1.3 pts
Q2 13:34 Defensive Holding on the Rams, 2 yards +3% JAX +0.7 pts
Q2 3:54 Fair Catch Interference on the Rams, 15 yards +4% JAX +1.4 pts
Q2 3:41 Defensive Holding on the Rams, 5 yards +2% JAX +0.4 pts
Q2 1:12 Roughing the Passer on the Jaguars, 15 yards +1% LA +1.0 pts
Q3 8:36 False Start on the Rams (Van Jefferson), 5 yards · pre-snap +1% JAX +0.5 pts
Q4 13:26 Roughing the Passer on the Jaguars, 14 yards 0% LA +1.7 pts
Q4 9:30 Defensive Holding on the Rams (Taylor Rapp), 5 yards, wiping out the play 0% JAX +2.5 pts
Q4 8:59 Offensive Holding on the Jaguars, 10 yards 0% LA +1.0 pts

Jaguars penalties, every game · Rams penalties, every game · All teams, 2021

When it happened

Rams’ chance of winning

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 Jaguars were.
#WhenWhat happenedWin probability forNext drive
1 Q1 12:30 The Rams were stopped on 3rd & 113rd & 4th downs · 26% expected +4% JAX LA: Field goal
2 Q1 11:54 The Jaguars fumbled and the Rams recoveredFumble bounces · loose balls are close to 50/50 +5% LA JAX: Punt
3 Q1 4:15 The Jaguars converted 3rd & 93rd & 4th downs · 24% expected +6% JAX JAX: Touchdown
4 Q1 1:34 The Jaguars converted 4th & 23rd & 4th downs · 54% expected +8% JAX JAX: Touchdown
5 Q2 15:00 The Jaguars converted 3rd & 83rd & 4th downs · 26% expected +6% JAX JAX: Touchdown
6 Q2 9:58 The Rams converted 4th & 13rd & 4th downs · 73% expected +7% LA LA: Field goal
7 Q2 8:27 The Rams were stopped on 3rd & 13rd & 4th downs · 74% expected +6% JAX LA: Field goal
8 Q2 3:54 Fair Catch Interference on the Rams, 15 yardsJudgment calls +4% JAX JAX: Punt

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.

  • Robert Woods (LA WR), out (IR) · 1.0 pts
  • Darrell Henderson (LA RB), out · 0.2 pts
  • Shaquill Griffin (JAX CB), out · 0.7 pts
  • Jamal Agnew (JAX WR), out (IR) · 0.3 pts
  • Dan Arnold (JAX TE), 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

Jaguars 0% · Rams 100%

Final margin
Rams by 30
Luck in points
0.5 for the Jaguars
Luck-adjusted margin
Rams by 30.5
Replay with same day's form
Jaguars 3% · Rams 97% 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 Week 13 2021 games · Jaguars · Rams

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