luckadjusted

Week 8 2021 · October 31, 2021

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

Cowboys at Vikings, Week 8 2021: who deserved to win?

The Cowboys beat the Vikings 20–16, and it was no fluke: replayed with the way both teams actually played, the Cowboys win 9 of 10. The Vikings had the bounces: injuries alone were worth 8.6 points to the Vikings.

An off day for the Vikings: their offense played far below its usual level. In a fresh game against the Cowboys they would win 58% of the time; with this day’s form, 7%. The numbers

Before kickoff the Vikings were 63% favorites. The biggest swing (Q4, 2:00 left): Illegal Use of Hands on the Vikings (Harrison Smith), 5 yards, wiping out the play, worth 38 points of win probability to the Cowboys.

Final

Dallas Cowboys 20
Minnesota Vikings 16

October 31, 2021 · U.S. Bank Stadium · Closing line: Vikings −4.5

Luck index +7 Cowboys about even · −7 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. Cowboys win 9, Vikings win 1.

  1. 1 DAL 42 MIN 6
  2. 2 DAL 49 MIN 21
  3. 3 DAL 36 MIN 13
  4. 4 DAL 26 MIN 6
  5. 5 DAL 30 MIN 14
  6. 6 DAL 26 MIN 13
  7. 7 DAL 20 MIN 10
  8. 8 DAL 27 MIN 20
  9. 9 DAL 26 MIN 23
  10. 10 DAL 16 MIN 23

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.

An off day for the Vikings

Their offense played far below its usual level. In a fresh game against the Cowboys they would win 58% of the time; with this day’s form, 7%.

51 points apart for the Vikings: the gap is how differently this game went from what the two teams usually are.

UnitThis gameUsual levelBetter or worse than usual
Cowboys offenseEPA per play gained +0.18 +0.15 better by 0.03
Cowboys defenseEPA per play allowed −0.23 +0.17 better by 0.40
Vikings offenseEPA per play gained −0.23 +0.16 worse by 0.39
Vikings defenseEPA per play allowed +0.18 +0.12 worse by 0.06

EPA (expected points added) per play on competitive snaps, turnovers left out because they are valued as luck. Usual level: the team’s earlier games this season plus half of last season, pulled toward the league average. One team’s defense and the other team’s offense are the same snaps, so one game can’t fully say whose day it was; it shows how far this one was from both teams’ norms.

How 4,000 replays ended

Cowboys win 93% of them, Vikings 7%, counting the 1% still level after regulation as half each. The line is what actually happened: Cowboys by 4.

Show as a table
Final margin in the replaysShare of replays
Cowboys by 17+59.4%
Cowboys by 9–1619.2%
Cowboys by 1–814.5%
Level after regulation0.7%
Vikings by 1–84.3%
Vikings by 9–161.5%
Vikings by 17+0.4%

Where the luck was

Take the luck out

The final margin was Cowboys by 4. Remove the luck, one kind at a time, and it becomes Cowboys by 17.9.

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.

  • G. Zuerlein, 43 yds missed · 84% expected
  • G. Zuerlein, 38 yds made · 90% expected
  • G. Joseph, 45 yds made · 81% expected
  • G. Joseph, 40 yds made · 89% expected
  • G. Zuerlein, 39 yds made · 89% expected
  • G. Joseph, 24 yds made · 99% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Vikings’ chance of winning

As low as 0% and as high as 79%. 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 Cowboys were.
#WhenWhat happenedWin probability forNext drive
1 Q2 2:49 The Vikings converted 4th & 13rd & 4th downs · 73% expected +10% MIN MIN: Field goal
2 Q3 14:18 The Cowboys converted 3rd & 83rd & 4th downs · 30% expected +22% DAL DAL: Touchdown
3 Q4 12:13 Offensive Holding on the Cowboys, 10 yards, wiping out the playJudgment calls +19% MIN MIN: Punt
4 Q4 11:22 The Cowboys converted 3rd & 133rd & 4th downs · 22% expected +12% DAL DAL: Turnover
5 Q4 2:54 G. Joseph made 24-yard field goalKicks · 99% expected for him +14% MIN MIN: Turnover on downs
6 Q4 2:00 Illegal Use of Hands on the Vikings (Harrison Smith), 5 yards, wiping out the playJudgment calls · 7 flags in 2693 snaps before, position avg 1 per 420 +38% DAL DAL: Touchdown
7 Q4 1:18 Offensive Holding on the Cowboys, 10 yardsJudgment calls +12% MIN MIN: Turnover on downs
8 Q4 1:04 The Cowboys converted 3rd & 113rd & 4th downs · 24% expectedDefensive Delay of Game on the Vikings, 5 yardsPre-snap flags +21% DAL DAL: 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.

  • Patrick Peterson (MIN CB), out (IR) · 1.6 pts
  • Dak Prescott (DAL QB), out, replaced by c.rush · 9.0 pts
  • Michael Gallup (DAL WR), out (IR) · 0.8 pts
  • Hunter Niswander (DAL P), out (IR) · 0.2 pts
  • Neville Gallimore (DAL DT), out (IR) · 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

Cowboys 90% · Vikings 10%

Final margin
Cowboys by 4
Luck in points
13.9 for the Vikings
Luck-adjusted margin
Cowboys by 17.9
Replay with same day's form
Cowboys 93% · Vikings 7% 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 8 2021 games · Cowboys · Vikings

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