luckadjusted

Week 13 2021 · December 5, 2021

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

Vikings at Lions, Week 13 2021: who deserved to win?

The Lions beat the Vikings 29–27, but the Vikings played well enough to win it: they take 8 of 10 replays with the same day's form. Luck ran their way: judgment calls alone were worth 22 points of win probability to the Lions.

Before kickoff the Vikings were 70% favorites. The game turned on a luck play (Q4, 0:04 left): the Lions converted 4th & 2, worth 67 points of win probability to the Lions.

Final

Minnesota Vikings 27
Detroit Lions 29

December 5, 2021 · Ford Field · Closing line: Vikings −7

Luck index +77 Lions very lucky · −77 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. Vikings win 8, Lions win 2.

  1. 1 MIN 36 DET 6
  2. 2 MIN 31 DET 10
  3. 3 MIN 37 DET 20
  4. 4 MIN 27 DET 14
  5. 5 MIN 31 DET 21
  6. 6 MIN 20 DET 13
  7. 7 MIN 43 DET 39
  8. 8 MIN 31 DET 28
  9. 9 MIN 23 DET 27
  10. 10 MIN 26 DET 40

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

Vikings win 77% of them, Lions 23%, counting the 2% still level after regulation as half each. The line is what actually happened: Lions by 2.

Show as a table
Final margin in the replaysShare of replays
Vikings by 17+31.1%
Vikings by 9–1620.9%
Vikings by 1–823.3%
Level after regulation2.3%
Lions by 1–811.7%
Lions by 9–167.2%
Lions by 17+3.5%

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 +9.7 points to the Lions: the final margin was Lions by 2, without the luck Vikings by 7.7. 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.

  • G. Joseph, 41 yds made · 88% expected
  • G. Joseph, 31 yds made · 96% expected
  • R. Patterson, 31 yds made · 96% expected
  • R. Patterson, 41 yds made · 88% expected
  • G. Joseph, 31 yds made · 96% expected
  • R. Patterson, 49 yds made · 76% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Vikings 7 for 66 yards, Lions 3 for 11 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
Q2 15:00 Unnecessary Roughness on the Vikings (Xavier Woods), 14 yards +4% DET +1.5 pts
Q2 5:51 Neutral Zone Infraction on the Vikings (Sheldon Richardson), 5 yards · pre-snap +1% DET +0.5 pts
Q2 0:15 Delay of Game on the Lions, 5 yards · pre-snap +1% MIN +0.5 pts
Q3 10:45 Offensive Holding on the Vikings (Tyler Conklin), 10 yards +2% DET +1.3 pts
Q3 3:34 Defensive Pass Interference on the Vikings (Bashaud Breeland), 17 yards +5% DET +1.1 pts
Q3 0:53 False Start on the Vikings, 5 yards · pre-snap +1% DET +0.7 pts
Q4 12:02 Roughing the Passer on the Lions (Charles Harris), 1 yard 0% MIN +0.1 pts
Q4 7:45 Offensive Holding on the Vikings (Luke Stocker), 10 yards +12% DET +1.7 pts
Q4 7:20 False Start on the Vikings, 5 yards · pre-snap +1% DET +0.4 pts
Q4 0:23 Delay of Game on the Lions, 5 yards · pre-snap +12% MIN +0.3 pts

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

When it happened

Lions’ chance of winning

As low as 20% 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 Lions were ahead in it, below while the Vikings were.
#WhenWhat happenedWin probability forNext drive
1 Q1 10:00 The Lions were stopped on 4th & 13rd & 4th downs · 73% expected +9% MIN DET: Punt
2 Q2 11:16 The Vikings fumbled and the Lions recoveredFumble bounces · loose balls are close to 50/50 +10% DET MIN: Punt
3 Q4 8:41 The Lions were stopped on 3rd & 43rd & 4th downs · 45% expected +16% MIN DET: Turnover
4 Q4 7:45 Offensive Holding on the Vikings (Luke Stocker), 10 yardsJudgment calls · 4 flags in 1504 snaps before, position avg 1 per 269 +12% DET DET: Turnover
5 Q4 4:08 The Lions were stopped on 4th & 13rd & 4th downs · 72% expectedThe Lions fumbled and the Vikings recoveredFumble bounces · loose balls are close to 50/50 +50% MIN DET: Touchdown
6 Q4 1:54 The Vikings converted 3rd & 33rd & 4th downs · 45% expected +16% MIN MIN: Touchdown
7 Q4 0:08 The Lions were stopped on 3rd & 23rd & 4th downs · 60% expected +9% MIN DET: Touchdown
8 Q4 0:04 The game turned hereThe Lions converted 4th & 23rd & 4th downs · 59% expected +67% DET –

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.

  • Matt Nelson (DET T), out · 0.6 pts
  • D'Andre Swift (DET RB), out · 0.4 pts
  • Quintez Cephus (DET WR), out (IR) · 0.3 pts
  • Trey Flowers (DET LB), out (IR) · 0.3 pts
  • Austin Seibert (DET K), out (IR) · 0.2 pts
  • Jalen Reeves-Maybin (DET LB), out · 0.1 pts
  • Patrick Peterson (MIN CB), out (IR) · 1.6 pts
  • Danielle Hunter (MIN DE), out (IR) · 1.2 pts
  • Everson Griffen (MIN DE), out (IR) · 0.9 pts
  • Christian Darrisaw (MIN T), out · 0.8 pts
  • Eric Kendricks (MIN LB), out · 0.5 pts
  • Anthony Barr (MIN LB), out · 0.5 pts
  • Dalvin Cook (MIN RB), out · 0.4 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

Vikings 71% · Lions 29%

Final margin
Lions by 2
Luck in points
9.7 for the Lions
Luck-adjusted margin
Vikings by 7.7
Replay with same day's form
Vikings 77% · Lions 23% 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 · Vikings · Lions

More from Week 13 2021