luckadjusted

Week 7 2021 · October 24, 2021

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

Lions at Rams, Week 7 2021: who deserved to win?

The Rams beat the Lions 28–19, and it was no fluke: replayed with the way both teams actually played, the Rams win 8 of 10.

Before kickoff the Rams were 90% favorites. The biggest swing (Q3, 0:23 left): the Rams converted 3rd & 12, worth 22 points of win probability to the Rams.

Final

Detroit Lions 19
Los Angeles Rams 28

October 24, 2021 · SoFi Stadium · Closing line: Rams −17

Luck index +15 Rams about even · −15 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 2, Rams win 8.

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

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 15% of them, Rams 85%, counting the 3% still level after regulation as half each. The line is what actually happened: Rams by 9.

Show as a table
Final margin in the replaysShare of replays
Lions by 17+1.5%
Lions by 9–164.0%
Lions by 1–89.0%
Level after regulation2.8%
Rams by 1–827.0%
Rams by 9–1623.0%
Rams by 17+32.7%

Where the luck was

Take the luck out

The final margin was Rams by 9. Remove the luck, one kind at a time, and it becomes Rams by 2.8.

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.

  • A. Seibert, 37 yds made · 92% expected
  • M. Gay, 33 yds made · 95% expected
  • A. Seibert, 47 yds made · 76% expected
  • A. Seibert, 41 yds made · 87% expected
  • A. Seibert, 31 yds made · 96% expected
  • M. Gay, 47 yds made · 80% 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 26% 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 Lions were.
#WhenWhat happenedWin probability forNext drive
1 Q1 12:21 The Lions converted 3rd & 93rd & 4th downs · 27% expected +21% DET DET: Touchdown
2 Q1 11:01 The Lions converted 4th & 73rd & 4th downs · 31% expected +13% DET DET: Field goal
3 Q2 8:41 The Rams converted 3rd & 73rd & 4th downs · 34% expected +11% LA LA: Touchdown
4 Q3 10:02 The Lions converted 4th & 83rd & 4th downs · 29% expected +17% DET DET: Turnover on downs
5 Q3 6:19 The Lions were stopped on 4th & 13rd & 4th downs · 71% expected +16% LA DET: Field goal
6 Q3 4:00 The Rams were stopped on 4th & 13rd & 4th downs · 73% expected +11% DET LA: Touchdown
7 Q3 0:23 The Rams converted 3rd & 123rd & 4th downs · 24% expected +22% LA LA: Touchdown
8 Q4 14:50 The Rams converted 3rd & 103rd & 4th downs · 28% expected +9% LA LA: 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.

  • Darious Williams (LA CB), out (IR) · 0.6 pts
  • Cam Akers (LA RB), out (IR) · 0.2 pts
  • Justin Hollins (LA LB), out (IR) · 0.1 pts
  • Taylor Decker (DET T), out (IR) · 1.1 pts
  • Frank Ragnow (DET C), out (IR) · 0.8 pts
  • Romeo Okwara (DET DE), out (IR) · 0.4 pts
  • Romeo Okwara (DET LB), out (IR) · 0.3 pts
  • Kevin Strong (DET DT), out (IR) · 0.3 pts
  • Quintez Cephus (DET WR), out (IR) · 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

Lions 22% · Rams 78%

Final margin
Rams by 9
Luck in points
6.2 for the Rams
Luck-adjusted margin
Rams by 2.8
Replay with same day's form
Lions 15% · Rams 85% 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 7 2021 games · Lions · Rams

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