luckadjusted

Week 1 2019 · September 8, 2019

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

Colts at Chargers, Week 1 2019: who deserved to win?

The Chargers beat the Colts 30–24, but it was a coin flip: replayed with the way both teams played, the Chargers win 6 of 10. Luck ran their way: kicks alone were worth 7.8 points to the Chargers.

Before kickoff the Chargers were 67% favorites. The biggest swing (Q4, 0:38 left): the Colts’ two-point try was good, worth 16 points of win probability to the Colts.

Final (OT)

Indianapolis Colts 24
Los Angeles Chargers 30

September 8, 2019 · StubHub Center · Closing line: Chargers −6

Luck index +43 Chargers lucky · −43 Colts

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. Colts win 4, Chargers win 6.

  1. 1 IND 38 LAC 16
  2. 2 IND 27 LAC 14
  3. 3 IND 24 LAC 17
  4. 4 IND 34 LAC 31
  5. 5 IND 24 LAC 26
  6. 6 IND 13 LAC 19
  7. 7 IND 19 LAC 28
  8. 8 IND 16 LAC 27
  9. 9 IND 13 LAC 30
  10. 10 IND 14 LAC 37

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

Colts win 43% of them, Chargers 57%, counting the 3% still level after regulation as half each. The line is what actually happened: Chargers by 6.

Show as a table
Final margin in the replaysShare of replays
Colts by 17+6.3%
Colts by 9–1613.0%
Colts by 1–820.9%
Level after regulation2.8%
Chargers by 1–826.7%
Chargers by 9–1617.0%
Chargers by 17+13.3%

Where the luck was

Take the luck out

The final margin was Chargers by 6. Remove the luck, one kind at a time, and it becomes Colts by 2.0.

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.

  • T. Long, 40 yds made · 86% expected
  • A. Vinatieri, 46 yds missed · 77% expected
  • A. Vinatieri, 44 yds made · 80% expected
  • A. Vinatieri, 29 yds missed · 96% expected
  • Extra point missed · 93% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Chargers’ chance of winning

As low as 40% 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 Chargers were ahead in it, below while the Colts were.
#WhenWhat happenedWin probability forNext drive
1 Q1 3:35 Unnecessary Roughness on the Colts, 2 yardsJudgment calls +10% LAC LAC: Touchdown
2 Q2 10:06 The Colts converted 3rd & 33rd & 4th downs · 45% expected +9% IND IND: Touchdown
3 Q2 6:38 Illegal Formation on the Chargers, 5 yards, wiping out the playPre-snap flags +8% IND IND: Punt
4 Q2 6:06 The Chargers converted 3rd & 133rd & 4th downs · 24% expected +15% LAC LAC: Touchdown
5 Q4 13:32 A. Vinatieri missed 29-yard field goalKicks · 96% expected for him +7% LAC IND: Touchdown
6 Q4 0:38 The Colts’ two-point try was good3rd & 4th downs · 47% expected +16% IND –
7 Q4 0:08 The Chargers converted 3rd & 63rd & 4th downs · 39% expected +13% IND LAC: Touchdown
8 QOT 5:46 The Chargers converted 3rd & 13rd & 4th downs · 68% expected +8% LAC LAC: 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.

  • Derwin James (LAC FS), out (IR) · 0.7 pts
  • Jatavis Brown (LAC LB), out · 0.3 pts
  • Jabaal Sheard (IND DE), out · 0.6 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

Colts 65% · Chargers 35%

Final margin
Chargers by 6
Luck in points
8.0 for the Chargers
Luck-adjusted margin
Colts by 2.0
Replay with same day's form
Colts 43% · Chargers 57% 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 2019 games · Colts · Chargers

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