luckadjusted

Week 9 2019 · November 3, 2019

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

Vikings at Chiefs, Week 9 2019: who deserved to win?

The Chiefs beat the Vikings 26–23, but it was a coin flip: replayed with the way both teams played, the Chiefs win 5 of 10. Luck ran their way: kicks alone were worth 44 points of win probability to the Chiefs.

Before kickoff the Vikings were 66% favorites. The game turned on a luck play (Q4, 2:36 left): H. Butker made 54-yard field goal, worth 15 points of win probability to the Chiefs. The biggest single swing (Q4, 0:03 left): H. Butker made 44-yard field goal.

Final

Minnesota Vikings 23
Kansas City Chiefs 26

November 3, 2019 · Arrowhead Stadium · Closing line: Vikings −5.5

Luck index +47 Chiefs lucky · −47 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 5, Chiefs win 5.

  1. 1 MIN 42 KC 18
  2. 2 MIN 23 KC 10
  3. 3 MIN 30 KC 21
  4. 4 MIN 32 KC 28
  5. 5 MIN 30 KC 28
  6. 6 MIN 34 KC 36
  7. 7 MIN 38 KC 43
  8. 8 MIN 19 KC 28
  9. 9 MIN 12 KC 27
  10. 10 MIN 10 KC 33

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 47% of them, Chiefs 53%, counting the 4% still level after regulation as half each. The line is what actually happened: Chiefs by 3.

Show as a table
Final margin in the replaysShare of replays
Vikings by 17+11.9%
Vikings by 9–1614.1%
Vikings by 1–820.3%
Level after regulation4.0%
Chiefs by 1–821.1%
Chiefs by 9–1614.8%
Chiefs by 17+13.9%

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 +3.7 points to the Vikings: the final margin was Chiefs by 3, without the luck Chiefs by 6.8. 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.

  • H. Butker, 24 yds made · 98% expected
  • D. Bailey, 29 yds made · 96% expected
  • H. Butker, 45 yds made · 74% expected
  • H. Butker, 54 yds made · 58% expected
  • H. Butker, 44 yds made · 78% expected
  • Extra point missed · 93% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Vikings 3 for 25 yards, Chiefs 4 for 25 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
Q1 7:23 Defensive Holding on the Chiefs, 5 yards +3% MIN +1.1 pts
Q1 6:22 Defensive Too Many Men on Field on the Chiefs, 5 yards · pre-snap +2% MIN +0.6 pts
Q3 13:33 Offensive Holding on the Vikings, 10 yards +5% KC +1.3 pts
Q3 8:27 Ineligible Downfield Pass on the Vikings, 5 yards, wiping out the play +6% KC +1.9 pts
Q3 4:06 Illegal Use of Hands on the Vikings, 10 yards, wiping out the play +8% KC +2.0 pts
Q4 9:04 Offensive Holding on the Chiefs (Travis Kelce), 10 yards, wiping out the play +16% MIN +2.3 pts
Q4 8:34 False Start on the Chiefs, 5 yards · pre-snap 0% MIN +0.5 pts

Vikings penalties, every game · Chiefs penalties, every game · All teams, 2019

When it happened

Chiefs’ chance of winning

As low as 23% 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 Chiefs were ahead in it, below while the Vikings were.
#WhenWhat happenedWin probability forNext drive
1 Q3 11:57 The Vikings converted 3rd & 43rd & 4th downs · 46% expected +13% MIN MIN: Touchdown
2 Q3 4:06 Illegal Use of Hands on the Vikings, 10 yards, wiping out the playJudgment calls +8% KC KC: Field goal
3 Q3 0:35 H. Butker made 45-yard field goalKicks · 74% expected for him, 1 of 3 from 45+ before +9% KC KC: Punt
4 Q4 11:03 The Vikings converted 3rd & 33rd & 4th downs · 44% expected +10% MIN MIN: Touchdown
5 Q4 9:04 Offensive Holding on the Chiefs (Travis Kelce), 10 yards, wiping out the playJudgment calls · 4 flags in 467 snaps before, position avg 1 per 253 +16% MIN MIN: Punt
6 Q4 7:58 The Vikings fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +14% MIN MIN: Punt
7 Q4 2:36 The game turned hereH. Butker made 54-yard field goalKicks · 58% expected for him, 2 of 4 from 45+ before +15% KC KC: Field goal
8 Q4 0:03 H. Butker made 44-yard field goalKicks · 78% expected for him +21% KC –

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 Mahomes (KC QB), out, replaced by m.moore · 5.9 pts
  • Frank Clark (KC DE), out · 0.8 pts
  • Eric Fisher (KC T), out · 0.7 pts
  • Kendall Fuller (KC CB), out · 0.6 pts
  • Alex Okafor (KC DE), out · 0.4 pts
  • Laurent Duvernay-Tardif (KC G), out · 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 64% · Chiefs 36%

Final margin
Chiefs by 3
Luck in points
3.7 for the Vikings
Luck-adjusted margin
Chiefs by 6.7
Replay with same day's form
Vikings 47% · Chiefs 53% 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 9 2019 games · Vikings · Chiefs

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