luckadjusted

Week 15 2023 · December 17, 2023

Chiefs at Patriots, Week 15 2023: who deserved to win?

The Chiefs beat the Patriots 27–17, and it was no fluke: replayed with the way both teams actually played, the Chiefs win 9 of 10. The Patriots had the bounces: drops alone were worth 2.6 points to the Patriots.

Before kickoff the Chiefs were 77% favorites. The biggest swing (Q2, 7:14 left): the Patriots converted 4th & 2, worth 17 points of win probability to the Patriots.

Final

Kansas City Chiefs 27
New England Patriots 17

December 17, 2023 · Gillette Stadium · Closing line: Chiefs −10

Luck index +8 Chiefs about even · −8 Patriots

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 9, Patriots win 1.

  1. 1 KC 44 NE 9
  2. 2 KC 30 NE 3
  3. 3 KC 45 NE 22
  4. 4 KC 26 NE 6
  5. 5 KC 27 NE 11
  6. 6 KC 27 NE 14
  7. 7 KC 20 NE 9
  8. 8 KC 20 NE 13
  9. 9 KC 27 NE 24
  10. 10 KC 17 NE 25

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 92% of them, Patriots 8%, counting the 1% still level after regulation as half each. The line is what actually happened: Chiefs by 10.

Show as a table
Final margin in the replaysShare of replays
Chiefs by 17+59.0%
Chiefs by 9–1617.9%
Chiefs by 1–814.6%
Level after regulation0.8%
Patriots by 1–85.9%
Patriots by 9–161.6%
Patriots by 17+0.4%

Where the luck was

Take the luck out

The final margin was Chiefs by 10. Remove the luck, one kind at a time, and it becomes Chiefs by 2.4.

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.

  • H. Butker, 39 yds missed · 90% expected
  • C. Ryland, 41 yds missed · 85% expected
  • C. Ryland, 25 yds made · 97% expected
  • H. Butker, 29 yds made · 98% expected
  • H. Butker, 54 yds made · 67% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Patriots’ chance of winning

As low as 0% and as high as 69%. 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 Patriots were ahead in it, below while the Chiefs were.
#WhenWhat happenedWin probability forNext drive
1 Q1 9:56 H. Butker missed 39-yard field goalKicks · 90% expected for him +10% NE KC: Touchdown
2 Q1 3:40 C. Ryland missed 41-yard field goalKicks · 85% expected for him +8% KC NE: Punt
3 Q2 7:14 The Patriots converted 4th & 23rd & 4th downs · 54% expected +17% NE NE: Touchdown
4 Q2 5:41 Offensive Holding on the Patriots, 10 yards, wiping out the playJudgment calls +14% KC KC: Touchdown
5 Q2 3:22 The Chiefs converted 3rd & 83rd & 4th downs · 33% expected +14% KC KC: Touchdown
6 Q2 2:09 The Chiefs converted 3rd & 93rd & 4th downs · 31% expected +9% KC KC: Touchdown
7 Q3 15:00 The Chiefs fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +8% KC KC: Field goal
8 Q3 13:40 Defensive Holding on the Patriots (Alex Austin), 5 yards, wiping out the playJudgment calls · 0 flags in 34 snaps before, position avg 1 per 216 +10% KC KC: Field goal

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.

  • JuJu Smith-Schuster (NE WR), out · 0.8 pts
  • Kendrick Bourne (NE WR), out (IR) · 0.7 pts
  • Rhamondre Stevenson (NE RB), out · 0.3 pts
  • Donovan Smith (KC T), out · 1.2 pts
  • Bryan Cook (KC FS), out (IR) · 0.4 pts
  • Isiah Pacheco (KC RB), 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

Chiefs 58% · Patriots 42%

Final margin
Chiefs by 10
Luck in points
7.6 for the Chiefs
Luck-adjusted margin
Chiefs by 2.4
Replay with same day's form
Chiefs 92% · Patriots 8% 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 15 2023 games · Chiefs · Patriots

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