luckadjusted

Week 12 2021 · November 28, 2021

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

Vikings at 49ers, Week 12 2021: who deserved to win?

The 49ers beat the Vikings 34–26, and it was no fluke: replayed with the way both teams actually played, the 49ers win 8 of 10. The Vikings had the bounces: judgment calls alone were worth 2.3 points to the Vikings.

Before kickoff the 49ers were 60% favorites. The biggest swing (Q3, 4:58 left): Return touchdown by the Vikings, worth 14 points of win probability to the Vikings.

Final

Minnesota Vikings 26
San Francisco 49ers 34

November 28, 2021 · Levi's Stadium · Closing line: 49ers −3.5

Luck index +17 49ers about even · −17 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 2, 49ers win 8.

  1. 1 MIN 27 SF 17
  2. 2 MIN 23 SF 20
  3. 3 MIN 28 SF 30
  4. 4 MIN 26 SF 31
  5. 5 MIN 26 SF 34
  6. 6 MIN 19 SF 30
  7. 7 MIN 6 SF 20
  8. 8 MIN 30 SF 48
  9. 9 MIN 3 SF 27
  10. 10 MIN 25 SF 54

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 17% of them, 49ers 83%, counting the 1% still level after regulation as half each. The line is what actually happened: 49ers by 8.

Show as a table
Final margin in the replaysShare of replays
Vikings by 17+1.4%
Vikings by 9–164.7%
Vikings by 1–810.5%
Level after regulation1.3%
49ers by 1–823.4%
49ers by 9–1621.1%
49ers by 17+37.6%

Where the luck was

Take the luck out

The final margin was 49ers by 8. Remove the luck, one kind at a time, and it becomes 49ers by 8.9.

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.

  • R. Gould, 46 yds made · 75% expected
  • R. Gould, 22 yds made · 98% expected
  • R. Gould, 42 yds missed · 83% expected
  • Extra point missed · 93% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

49ers’ chance of winning

As low as 30% 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 49ers were ahead in it, below while the Vikings were.
#WhenWhat happenedWin probability forNext drive
1 Q1 12:09 The 49ers were stopped on 3rd & 123rd & 4th downs · 25% expected +8% MIN SF: Touchdown
2 Q1 8:32 The Vikings converted 4th & 23rd & 4th downs · 51% expected +8% MIN MIN: Touchdown
3 Q1 7:42 The 49ers converted 3rd & 133rd & 4th downs · 23% expected +9% SF SF: Touchdown
4 Q2 0:35 The 49ers converted 3rd & 113rd & 4th downs · 26% expected +8% SF SF: Touchdown
5 Q3 4:58 Return touchdown by the VikingsSpecial teams +14% MIN MIN: Touchdown
6 Q4 12:46 The Vikings converted 3rd & 93rd & 4th downs · 29% expected +9% MIN MIN: Turnover on downs
7 Q4 9:13 The Vikings were stopped on 3rd & 33rd & 4th downs · 43% expected +8% SF MIN: Turnover on downs
8 Q4 9:09 The Vikings were stopped on 4th & 33rd & 4th downs · 42% expected +9% SF MIN: Turnover on downs

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.

  • Mike McGlinchey (SF T), out (IR) · 0.9 pts
  • Mohamed Sanu (SF WR), out (IR) · 0.4 pts
  • Javon Kinlaw (SF DT), out (IR) · 0.3 pts
  • Danielle Hunter (MIN DE), out (IR) · 1.2 pts
  • Everson Griffen (MIN DE), out (IR) · 0.8 pts
  • Dalvin Tomlinson (MIN DT), 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

Vikings 4% · 49ers 96%

Final margin
49ers by 8
Luck in points
0.9 for the Vikings
Luck-adjusted margin
49ers by 8.9
Replay with same day's form
Vikings 17% · 49ers 83% 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 12 2021 games · Vikings · 49ers

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