luckadjusted

Week 13 2020 · December 6, 2020

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

Rams at Cardinals, Week 13 2020: who deserved to win?

The Rams beat the Cardinals 38–28, and it was no fluke: replayed with the way both teams actually played, the Rams win 9 of 10. The Cardinals had the bounces: judgment calls alone were worth 5.4 points to the Cardinals.

Before kickoff the Rams were 57% favorites. The biggest swing (Q3, 6:58 left): the Cardinals converted 4th & 12, worth 12 points of win probability to the Cardinals.

Final

Los Angeles Rams 38
Arizona Cardinals 28

December 6, 2020 · State Farm Stadium · Closing line: Rams −2.5

Luck index +9 Rams about even · −9 Cardinals

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 9, Cardinals win 1.

  1. 1 LA 34 ARI 0
  2. 2 LA 30 ARI 3
  3. 3 LA 44 ARI 23
  4. 4 LA 31 ARI 13
  5. 5 LA 41 ARI 27
  6. 6 LA 38 ARI 27
  7. 7 LA 28 ARI 20
  8. 8 LA 35 ARI 30
  9. 9 LA 36 ARI 34
  10. 10 LA 22 ARI 31

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 91% of them, Cardinals 9%, counting the 2% still level after regulation as half each. The line is what actually happened: Rams by 10.

Show as a table
Final margin in the replaysShare of replays
Rams by 17+51.1%
Rams by 9–1621.6%
Rams by 1–816.9%
Level after regulation1.6%
Cardinals by 1–86.1%
Cardinals by 9–162.1%
Cardinals by 17+0.7%

Where the luck was

Take the luck out

The final margin was Rams by 10. Remove the luck, one kind at a time, and it becomes Rams by 17.8.

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.

  • Z. Gonzalez, 48 yds missed · 76% expected
  • M. Gay, 39 yds made · 89% expected
  • M. Gay, 37 yds missed · 91% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Cardinals’ chance of winning

As low as 0% and as high as 78%. 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 Cardinals were ahead in it, below while the Rams were.
#WhenWhat happenedWin probability forNext drive
1 Q1 14:26 Face Mask on the Rams (Leonard Floyd), 15 yards, wiping out the playJudgment calls · 4 flags in 1583 snaps before, position avg 1 per 402 +9% ARI ARI: Touchdown
2 Q2 5:28 The Rams were stopped on 4th & 13rd & 4th downs · 68% expected +11% ARI LA: Touchdown
3 Q2 0:08 Z. Gonzalez missed 48-yard field goalKicks · 76% expected for him, 13 of 19 from 45+ before +7% LA ARI: Touchdown
4 Q3 13:45 The Rams converted 3rd & 73rd & 4th downs · 36% expected +9% LA LA: Field goal
5 Q3 6:58 The Cardinals converted 4th & 123rd & 4th downs · 22% expected +12% ARI ARI: Touchdown
6 Q4 14:00 The Rams fumbled and the Cardinals recoveredFumble bounces · loose balls are close to 50/50 +10% ARI LA: Touchdown
7 Q4 12:10 The Rams converted 3rd & 113rd & 4th downs · 28% expected +10% LA LA: Touchdown
8 Q4 4:42 The Cardinals were stopped on 3rd & 93rd & 4th downs · 28% expectedReturn touchdown by the RamsSpecial teams +10% LA ARI: 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.

  • Larry Fitzgerald (ARI WR), out (IR) · 0.9 pts
  • Chandler Jones (ARI LB), out (IR) · 0.5 pts
  • Jalen Thompson (ARI S), out · 0.4 pts
  • Corey Peters (ARI DL), out (IR) · 0.3 pts
  • Andrew Whitworth (LA OL), out (IR) · 0.7 pts
  • Taylor Rapp (LA S), out (IR) · 0.5 pts
  • Kai Forbath (LA K), out (IR) · 0.3 pts
  • Micah Kiser (LA ILB), 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

Rams 100% · Cardinals 0%

Final margin
Rams by 10
Luck in points
7.8 for the Cardinals
Luck-adjusted margin
Rams by 17.8
Replay with same day's form
Rams 91% · Cardinals 9% 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 2020 games · Rams · Cardinals

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