luckadjusted

Week 1 2020 · September 10, 2020

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

Texans at Chiefs, Week 1 2020: who deserved to win?

The Chiefs beat the Texans 34–20 and were the better team on the day: replayed with the same form, they win 7 of 10.

Before kickoff the Chiefs were 76% favorites. The biggest swing (Q2, 14:17 left): the Chiefs converted 3rd & 6, worth 10 points of win probability to the Chiefs.

Final

Houston Texans 20
Kansas City Chiefs 34

September 10, 2020 · Arrowhead Stadium · Closing line: Chiefs −9.5

Luck index +30 Chiefs lucky · −30 Texans

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. Texans win 3, Chiefs win 7.

  1. 1 HOU 23 KC 7
  2. 2 HOU 34 KC 27
  3. 3 HOU 38 KC 35
  4. 4 HOU 24 KC 26
  5. 5 HOU 28 KC 33
  6. 6 HOU 21 KC 28
  7. 7 HOU 21 KC 31
  8. 8 HOU 24 KC 37
  9. 9 HOU 13 KC 31
  10. 10 HOU 16 KC 41

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

Texans win 30% of them, Chiefs 70%, counting the 4% still level after regulation as half each. The line is what actually happened: Chiefs by 14.

Show as a table
Final margin in the replaysShare of replays
Texans by 17+3.2%
Texans by 9–167.1%
Texans by 1–816.3%
Level after regulation4.5%
Chiefs by 1–827.6%
Chiefs by 9–1621.1%
Chiefs by 17+20.3%

Where the luck was

Take the luck out

The final margin was Chiefs by 14. Remove the luck, one kind at a time, and it becomes Chiefs by 1.8.

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.

  • K. Fairbairn, 51 yds missed · 66% expected
  • H. Butker, 29 yds made · 97% expected
  • H. Butker, 19 yds made · 100% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Chiefs’ chance of winning

As low as 35% and as high as 100%. 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 Texans were.
#WhenWhat happenedWin probability forNext drive
1 Q1 14:21 The Texans were stopped on 3rd & 103rd & 4th downs · 29% expectedFalse Start on the Texans, 5 yardsPre-snap flags +5% KC HOU: Punt
2 Q1 6:19 The Texans converted 3rd & 23rd & 4th downs · 62% expected +6% HOU HOU: Touchdown
3 Q1 3:38 The Chiefs were stopped on 3rd & 23rd & 4th downs · 64% expected +4% HOU KC: Touchdown
4 Q1 3:00 The Chiefs converted 4th & 13rd & 4th downs · 76% expected +5% KC KC: Touchdown
5 Q2 14:17 The Chiefs converted 3rd & 63rd & 4th downs · 33% expected +10% KC KC: Touchdown
6 Q2 2:30 The Chiefs converted 3rd & 23rd & 4th downs · 56% expected +5% KC KC: Touchdown
7 Q2 0:36 The Texans were stopped on 3rd & 103rd & 4th downs · 29% expected +5% KC HOU: Missed field goal
8 Q2 0:30 K. Fairbairn missed 51-yard field goalKicks · 66% expected for him, 4 of 9 from 45+ before +4% KC HOU: Punt

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.

  • Gareon Conley (HOU CB), out (IR) · 0.6 pts
  • Keke Coutee (HOU WR), 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

Texans 40% · Chiefs 60%

Final margin
Chiefs by 14
Luck in points
12.2 for the Chiefs
Luck-adjusted margin
Chiefs by 1.8
Replay with same day's form
Texans 30% · Chiefs 70% 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 1 2020 games · Texans · Chiefs

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