luckadjusted

Week 5 2023 · October 8, 2023

Chiefs at Vikings, Week 5 2023: who deserved to win?

The Chiefs beat the Vikings 27–20 and were the better team on the day: replayed with the same form, they win 8 of 10. The Vikings had the bounces: judgment calls alone were worth 12 points of win probability to the Vikings.

Before kickoff the Chiefs were 60% favorites. The biggest swing (Q4, 4:54 left): the Vikings were stopped on 4th & 12, worth 13 points of win probability to the Chiefs.

Final

Kansas City Chiefs 27
Minnesota Vikings 20

October 8, 2023 · U.S. Bank Stadium · Closing line: Chiefs −3.5

Luck index +22 Chiefs about even · −22 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. Chiefs win 8, Vikings win 2.

  1. 1 KC 34 MIN 10
  2. 2 KC 24 MIN 6
  3. 3 KC 27 MIN 14
  4. 4 KC 23 MIN 13
  5. 5 KC 28 MIN 21
  6. 6 KC 20 MIN 14
  7. 7 KC 27 MIN 24
  8. 8 KC 9 MIN 7
  9. 9 KC 17 MIN 20
  10. 10 KC 10 MIN 21

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

Chiefs win 78% of them, Vikings 22%, counting the 5% still level after regulation as half each. The line is what actually happened: Chiefs by 7.

Show as a table
Final margin in the replaysShare of replays
Chiefs by 17+19.7%
Chiefs by 9–1623.4%
Chiefs by 1–831.7%
Level after regulation4.9%
Vikings by 1–813.7%
Vikings by 9–165.2%
Vikings by 17+1.4%

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 +0.1 points to the Chiefs: the final margin was Chiefs by 7, without the luck Chiefs by 6.9. 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, 40 yds made · 89% expected
  • H. Butker, 38 yds made · 92% expected
  • G. Joseph, 29 yds made · 97% expected
  • H. Butker, 40 yds made · 90% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Chiefs 10 for 86 yards, Vikings 4 for 51 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 5:50 Defensive Holding on the Chiefs (Tershawn Wharton), 5 yards +3% MIN +1.3 pts
Q2 12:46 Unnecessary Roughness on the Chiefs (Justin Reid), 15 yards +4% MIN +2.5 pts
Q2 11:50 Illegal Contact on the Chiefs (L'Jarius Sneed), 5 yards +2% MIN +0.8 pts
Q2 10:11 Defensive Pass Interference on the Chiefs (Trent McDuffie), 11 yards +7% MIN +2.4 pts
Q2 10:07 Illegal Use of Hands on the Chiefs (L'Jarius Sneed), 5 yards +2% MIN +0.7 pts
Q2 9:40 Offensive Holding on the Vikings, 10 yards, wiping out the play +6% KC +2.2 pts
Q2 7:13 Fair Catch Interference on the Chiefs (Nic Jones), 15 yards +1% MIN +1.4 pts
Q2 0:09 Delay of Game on the Chiefs, 5 yards · pre-snap +1% MIN +0.1 pts
Q3 6:05 Defensive Pass Interference on the Vikings (Harrison Smith), 31 yards +10% KC +3.8 pts
Q3 5:58 Illegal Crackback on the Chiefs (Travis Kelce), 15 yards +5% MIN +1.4 pts
Q4 9:05 Delay of Game on the Chiefs, 5 yards · pre-snap +1% MIN +0.8 pts
Q4 8:55 Illegal Formation on the Vikings, 5 yards · pre-snap +3% KC +1.3 pts
Q4 4:54 Delay of Game on the Vikings, 5 yards · pre-snap +1% KC +0.1 pts
Q4 0:06 Defensive Offside on the Chiefs (Chris Jones), 5 yards · pre-snap +1% MIN +0.3 pts

Chiefs penalties, every game · Vikings penalties, every game · All teams, 2023

When it happened

Vikings’ chance of winning

As low as 0% and as high as 61%. 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 Chiefs were.
#WhenWhat happenedWin probability forNext drive
1 Q1 6:29 The Vikings converted 4th & 53rd & 4th downs · 39% expected +9% MIN MIN: Field goal
2 Q1 4:10 The Vikings were stopped on 3rd & 73rd & 4th downs · 33% expectedT. Hockenson dropped a catchable passDrops · 2 drops on 140 catchable balls before this +8% KC MIN: Field goal
3 Q2 5:06 The Vikings converted 4th & 23rd & 4th downs · 58% expected +11% MIN MIN: Touchdown
4 Q3 13:45 The Chiefs converted 3rd & 183rd & 4th downs · 20% expected +12% KC KC: Touchdown
5 Q3 10:13 The Chiefs converted 3rd & 83rd & 4th downs · 27% expected +13% KC KC: Touchdown
6 Q3 8:29 The Chiefs converted 3rd & 73rd & 4th downs · 36% expected +8% KC KC: Touchdown
7 Q3 6:05 Defensive Pass Interference on the Vikings (Harrison Smith), 31 yardsJudgment calls · 11 flags in 4645 snaps before, position avg 1 per 462 +10% KC KC: Touchdown
8 Q4 4:54 The Vikings were stopped on 4th & 123rd & 4th downs · 23% expectedDelay of Game on the Vikings, 5 yardsPre-snap flags +13% KC MIN: End of game

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.

  • Nick Bolton (KC LB), out · 0.5 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

Chiefs 79% · Vikings 21%

Final margin
Chiefs by 7
Luck in points
0.1 for the Chiefs
Luck-adjusted margin
Chiefs by 6.9
Replay with same day's form
Chiefs 78% · Vikings 22% 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; injuries from snap counts and injury reports.

Methodology and validation · All Week 5 2023 games · Chiefs · Vikings

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