luckadjusted

Divisional round 2020 · January 17, 2021

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

Browns at Chiefs, Divisional round 2020: who deserved to win?

The Chiefs beat the Browns 22–17, and it was no fluke: replayed with the way both teams actually played, the Chiefs win 9 of 10. The Browns had the bounces: kicks alone were worth 4.1 points to the Browns.

Before kickoff the Chiefs were 71% favorites.

Final

Cleveland Browns 17
Kansas City Chiefs 22

January 17, 2021 · Arrowhead Stadium · Closing line: Chiefs −7.5

Luck index +14 Chiefs about even · −14 Browns

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. Browns win 1, Chiefs win 9.

  1. 1 CLE 21 KC 16
  2. 2 CLE 21 KC 23
  3. 3 CLE 10 KC 14
  4. 4 CLE 13 KC 20
  5. 5 CLE 14 KC 22
  6. 6 CLE 20 KC 31
  7. 7 CLE 10 KC 24
  8. 8 CLE 10 KC 27
  9. 9 CLE 10 KC 31
  10. 10 CLE 9 KC 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

Browns win 14% of them, Chiefs 86%, counting the 2% still level after regulation as half each. The line is what actually happened: Chiefs by 5.

Show as a table
Final margin in the replaysShare of replays
Browns by 17+1.0%
Browns by 9–163.8%
Browns by 1–88.6%
Level after regulation2.2%
Chiefs by 1–827.7%
Chiefs by 9–1623.2%
Chiefs by 17+33.5%

Where the luck was

Take the luck out

The final margin was Chiefs by 5. Remove the luck, one kind at a time, and it becomes Chiefs by 12.7.

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.

  • C. Parkey, 46 yds made · 76% expected
  • H. Butker, 50 yds made · 70% expected
  • H. Butker, 28 yds made · 98% expected
  • H. Butker, 33 yds missed · 94% expected
  • H. Butker, 33 yds made · 94% expected
  • Extra point missed · 93% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Chiefs’ chance of winning

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 Browns were.
#WhenWhat happenedWin probability forNext drive
1 Q1 7:42 The Browns converted 3rd & 103rd & 4th downs · 26% expected +6% CLE CLE: Field goal
2 Q2 14:25 Offensive Holding on the Chiefs, 10 yards, wiping out the playJudgment calls +6% CLE CLE: Punt
3 Q2 11:17 Offensive Holding on the Browns, 10 yards, wiping out the playJudgment calls +6% KC KC: Field goal
4 Q4 12:18 The Browns converted 4th & 33rd & 4th downs · 50% expected +5% CLE CLE: Touchdown
5 Q4 11:11 The Browns converted 3rd & 33rd & 4th downs · 42% expected +7% CLE CLE: Touchdown
6 Q4 9:24 The Chiefs converted 3rd & 53rd & 4th downs · 46% expected +6% KC KC: Turnover
7 Q4 6:02 The Browns converted 4th & 13rd & 4th downs · 73% expected +8% CLE CLE: Punt
8 Q4 2:00 The Chiefs were stopped on 3rd & 143rd & 4th downs · 27% expected +5% KC KC: 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.

  • Sammy Watkins (KC WR), out · 0.7 pts
  • Clyde Edwards-Helaire (KC RB), out · 0.1 pts
  • Olivier Vernon (CLE DE), out (IR) · 1.0 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

Browns 1% · Chiefs 99%

Final margin
Chiefs by 5
Luck in points
7.7 for the Browns
Luck-adjusted margin
Chiefs by 12.7
Replay with same day's form
Browns 14% · Chiefs 86% 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 Divisional round 2020 games · Browns · Chiefs

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