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. The Dolphins had the bounces: fumble bounces alone were worth 1.6 points to the Dolphins.

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 34 MIA 19
  4. 4 KC 30 MIA 19
  5. 5 KC 41 MIA 34
  6. 6 KC 30 MIA 26
  7. 7 KC 31 MIA 29
  8. 8 KC 27 MIA 30
  9. 9 KC 28 MIA 39
  10. 10 KC 16 MIA 38

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

Take the luck out

The final margin was Chiefs by 6. Remove the luck, one kind at a time, and it becomes Chiefs by 1.1.

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.

  • 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.

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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