luckadjusted

Week 16 2021 · December 26, 2021

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

Rams at Vikings, Week 16 2021: who deserved to win?

The Rams beat the Vikings 30–23, and it was no fluke: replayed with the way both teams actually played, the Rams win 8 of 10.

Before kickoff the Rams were 60% favorites. The biggest swing (Q3, 7:22 left): Return touchdown by the Rams, worth 18 points of win probability to the Rams.

Final

Los Angeles Rams 30
Minnesota Vikings 23

December 26, 2021 · U.S. Bank Stadium · Closing line: Rams −3.5

Luck index +15 Rams about even · −15 Vikings

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 8, Vikings win 2.

  1. 1 LA 45 MIN 12
  2. 2 LA 41 MIN 17
  3. 3 LA 38 MIN 20
  4. 4 LA 42 MIN 27
  5. 5 LA 32 MIN 21
  6. 6 LA 16 MIN 7
  7. 7 LA 30 MIN 24
  8. 8 LA 34 MIN 31
  9. 9 LA 16 MIN 20
  10. 10 LA 14 MIN 27

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 85% of them, Vikings 15%, counting the 1% still level after regulation as half each. The line is what actually happened: Rams by 7.

Show as a table
Final margin in the replaysShare of replays
Rams by 17+41.4%
Rams by 9–1623.4%
Rams by 1–818.9%
Level after regulation1.5%
Vikings by 1–89.6%
Vikings by 9–163.5%
Vikings by 17+1.7%

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 Vikings: the final margin was Rams by 7, without the luck Rams by 7.5. 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, 32 yds made · 96% expected
  • G. Joseph, 23 yds made · 99% expected
  • M. Gay, 31 yds made · 97% expected
  • G. Joseph, 24 yds made · 99% expected
  • M. Gay, 24 yds made · 99% expected
  • G. Joseph, 44 yds made · 84% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Rams 1 for 5 yards, Vikings 2 for 20 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
Q3 11:01 Defensive Offside on the Rams (Nick Scott), 5 yards · pre-snap +2% MIN +0.5 pts
Q3 8:33 False Start on the Vikings, 5 yards · pre-snap +4% LA +0.6 pts
Q3 7:22 Unsportsmanlike Conduct on the Vikings (Harrison Smith), 15 yards +3% LA +1.2 pts

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

When it happened

Vikings’ chance of winning

As low as 0% and as high as 55%. 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 Vikings were ahead in it, below while the Rams were.
#WhenWhat happenedWin probability forNext drive
1 Q1 10:44 The Rams converted 4th & 13rd & 4th downs · 70% expectedThe Rams fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +12% LA LA: Touchdown
2 Q1 0:17 The Vikings were stopped on 3rd & 83rd & 4th downs · 25% expected +11% LA MIN: Punt
3 Q2 4:11 The Rams were stopped on 3rd & 63rd & 4th downs · 34% expected +10% MIN LA: Field goal
4 Q2 2:38 G. Joseph made 23-yard field goalKicks · 99% expected for him +6% LA MIN: End of half
5 Q3 14:05 The Vikings fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +6% MIN MIN: Punt
6 Q3 7:22 Unsportsmanlike Conduct on the Vikings (Harrison Smith), 15 yardsJudgment calls · 10 flags in 3142 snaps before, position avg 1 per 420Return touchdown by the RamsSpecial teams +18% LA LA: Opp touchdown
7 Q3 1:39 The Vikings were stopped on 3rd & 63rd & 4th downs · 30% expected +6% LA MIN: Field goal
8 Q4 7:00 The Rams converted 3rd & 63rd & 4th downs · 34% expected +6% LA LA: 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.

  • Everson Griffen (MIN DE), out (IR) · 0.9 pts
  • Mason Cole (MIN C), out (IR) · 0.5 pts
  • Dalvin Cook (MIN RB), out (IR) · 0.5 pts
  • Andrew Whitworth (LA T), out (IR) · 1.1 pts
  • Robert Woods (LA WR), out (IR) · 1.0 pts
  • Terrell Lewis (LA LB), out · 0.1 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 95% · Vikings 5%

Final margin
Rams by 7
Luck in points
0.5 for the Vikings
Luck-adjusted margin
Rams by 7.5
Replay with same day's form
Rams 85% · Vikings 15% 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 16 2021 games · Rams · Vikings

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