luckadjusted

Week 14 2020 · December 13, 2020

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

Chiefs at Dolphins, Week 14 2020: who deserved to win?

The Chiefs beat the Dolphins 33–27 and were the better team on the day: replayed with the same form, they win 7 of 10.

Before kickoff the Chiefs were 71% favorites. The biggest swing (Q1, 3:47 left): the Dolphins converted 3rd & 11, worth 11 points of win probability to the Dolphins.

Final

Kansas City Chiefs 33
Miami Dolphins 27

December 13, 2020 · Hard Rock Stadium · Closing line: Chiefs −7.5

Luck index +34 Chiefs lucky · −34 Dolphins

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 7, Dolphins win 3.

  1. 1 KC 41 MIA 10
  2. 2 KC 30 MIA 10
  3. 3 KC 35 MIA 20
  4. 4 KC 44 MIA 33
  5. 5 KC 37 MIA 30
  6. 6 KC 37 MIA 33
  7. 7 KC 37 MIA 35
  8. 8 KC 27 MIA 30
  9. 9 KC 24 MIA 35
  10. 10 KC 14 MIA 36

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 66% of them, Dolphins 34%, counting the 3% still level after regulation as half each. The line is what actually happened: Chiefs by 6.

Show as a table
Final margin in the replaysShare of replays
Chiefs by 17+23.7%
Chiefs by 9–1617.3%
Chiefs by 1–822.4%
Level after regulation2.9%
Dolphins by 1–816.1%
Dolphins by 9–169.3%
Dolphins by 17+8.3%

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 +4.9 points to the Chiefs: the final margin was Chiefs by 6, without the luck Chiefs by 1.1. 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.

  • J. Sanders, 45 yds missed · 81% expected
  • J. Sanders, 31 yds made · 96% expected
  • H. Butker, 46 yds made · 79% expected
  • J. Sanders, 44 yds made · 81% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Chiefs 8 for 56 yards, Dolphins 3 for 35 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 9:31 Illegal Shift on the Chiefs, 5 yards · pre-snap +2% MIA +1.1 pts
Q2 13:58 Ineligible Downfield Pass on the Dolphins, 5 yards, wiping out the play +5% KC +2.2 pts
Q2 8:10 Unnecessary Roughness on the Chiefs (Anthony Hitchens), 15 yards +2% MIA +0.9 pts
Q2 2:48 Roughing the Passer on the Dolphins (Shaq Lawson), 15 yards +7% KC +1.8 pts
Q3 5:27 False Start on the Chiefs (Willie Gay Jr.), 5 yards · pre-snap 0% MIA +0.4 pts
Q4 10:54 False Start on the Chiefs (Nick Keizer), 5 yards · pre-snap 0% MIA +1.2 pts
Q4 5:38 Defensive Offside on the Chiefs (Frank Clark), 4 yards · pre-snap +1% KC +0.2 pts
Q4 5:16 Defensive Pass Interference on the Chiefs, 3 yards +2% MIA +0.6 pts
Q4 4:30 Defensive Pass Interference on the Chiefs (Anthony Hitchens), 1 yard +1% MIA +0.7 pts
Q4 3:33 Face Mask on the Dolphins (Xavien Howard), 15 yards +4% KC +1.7 pts
Q4 0:42 Defensive Pass Interference on the Chiefs, 18 yards 0% KC +1.0 pts

Chiefs penalties, every game · Dolphins penalties, every game · All teams, 2020

When it happened

Dolphins’ chance of winning

As low as 0% and as high as 83%. 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 Dolphins were ahead in it, below while the Chiefs were.
#WhenWhat happenedWin probability forNext drive
1 Q1 9:08 The Dolphins fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +6% MIA MIA: Missed field goal
2 Q1 7:04 The Dolphins were stopped on 3rd & 33rd & 4th downs · 50% expected +6% KC MIA: Missed field goal
3 Q1 7:01 J. Sanders missed 45-yard field goalKicks · 81% expected for him, 22 of 29 from 45+ before +8% KC MIA: Touchdown
4 Q1 6:56 The Chiefs fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +6% KC KC: Punt
5 Q1 3:47 The Dolphins converted 3rd & 113rd & 4th downs · 24% expected +11% MIA MIA: Touchdown
6 Q1 2:27 The Dolphins converted 3rd & 43rd & 4th downs · 44% expected +6% MIA MIA: Touchdown
7 Q2 2:48 Roughing the Passer on the Dolphins (Shaq Lawson), 15 yardsJudgment calls · 4 flags in 1085 snaps before, position avg 1 per 259 +7% KC KC: Touchdown
8 Q3 13:04 Return touchdown by the ChiefsSpecial teams +7% KC KC: Opp 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.

  • Preston Williams (MIA WR), out (IR) · 0.5 pts
  • Ereck Flowers (MIA G), out · 0.5 pts
  • Kyle Van Noy (MIA LB), out · 0.4 pts
  • Salvon Ahmed (MIA RB), out · 0.2 pts
  • Myles Gaskin (MIA RB), out (IR) · 0.1 pts
  • Mitchell Schwartz (KC T), out (IR) · 0.8 pts
  • Damien Wilson (KC LB), out · 0.2 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 62% · Dolphins 38%

Final margin
Chiefs by 6
Luck in points
4.9 for the Chiefs
Luck-adjusted margin
Chiefs by 1.1
Replay with same day's form
Chiefs 66% · Dolphins 34% 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 14 2020 games · Chiefs · Dolphins

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