luckadjusted

Week 8 2023 · October 29, 2023

Bears at Chargers, Week 8 2023: who deserved to win?

The Chargers beat the Bears 30–13 and were the better team on the day: replayed with the same form, they win 6 of 10.

Before kickoff the Chargers were 76% favorites.

Final

Chicago Bears 13
Los Angeles Chargers 30

October 29, 2023 · SoFi Stadium · Closing line: Chargers −9.5

Luck index +37 Chargers lucky · −37 Bears

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. Bears win 4, Chargers win 6.

  1. 1 CHI 33 LAC 10
  2. 2 CHI 34 LAC 21
  3. 3 CHI 20 LAC 13
  4. 4 CHI 23 LAC 20
  5. 5 CHI 14 LAC 16
  6. 6 CHI 20 LAC 25
  7. 7 CHI 16 LAC 24
  8. 8 CHI 17 LAC 30
  9. 9 CHI 21 LAC 38
  10. 10 CHI 7 LAC 33

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

Bears win 37% of them, Chargers 63%, counting the 2% still level after regulation as half each. The line is what actually happened: Chargers by 17.

Show as a table
Final margin in the replaysShare of replays
Bears by 17+5.1%
Bears by 9–169.4%
Bears by 1–820.3%
Level after regulation2.3%
Chargers by 1–826.2%
Chargers by 9–1619.5%
Chargers by 17+17.2%

Where the luck was

What the luck was worth

Every lucky and unlucky play, weighted by the moment it happened: its swing in win probability, added up by kind. A missed kick in a decided game counts for nothing; the same kick at the end of a tie game can be most of a win.

Swings add up across a game, so in one that went back and forth they can pass 100%. On the scoreboard the same luck was worth +9.1 points to the Chargers: the final margin was Chargers by 17, without the luck Chargers by 7.9. Luck shares are the fitted ones (how much of each kind 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. Dicker, 43 yds made · 85% expected
  • C. Dicker, 53 yds made · 70% expected
  • C. Dicker, 46 yds made · 82% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Bears 7 for 53 yards, Chargers 2 for 15 yards

Every accepted flag, in order, and what it did to the helped team’s chance of winning at that moment, including any play it wiped out (points on the scoreboard in grey). A flag in a decided game is worth nothing; one at the turn of a close game can be worth most of a win. Judgment calls count toward luck, pre-snap fouls mostly don’t. How calls are valued

WhenFlagWin probability for
Q1 6:32 Illegal Use of Hands on the Bears, 10 yards, wiping out the play +6% LAC +3.0 pts
Q1 5:17 Fair Catch Interference on the Bears (Velus Jones Jr.), 15 yards +3% LAC +1.5 pts
Q2 10:19 Defensive Pass Interference on the Bears (Tyrique Stevenson), 8 yards +1% LAC +1.6 pts
Q2 4:28 Illegal Shift on the Bears, 5 yards · pre-snap +2% LAC +1.2 pts
Q2 0:56 Defensive Offside on the Bears (DeMarcus Walker), 5 yards · pre-snap 0% LAC +0.5 pts
Q3 12:37 Defensive Offside on the Bears (Andrew Billings), 5 yards, wiping out the play · pre-snap +3% LAC +2.7 pts
Q3 11:54 False Start on the Chargers (Donald Parham), 5 yards · pre-snap 0% CHI +0.8 pts
Q3 11:00 Offensive Holding on the Chargers, 10 yards 0% CHI +0.8 pts
Q3 5:24 False Start on the Bears (Marcedes Lewis), 5 yards · pre-snap +1% LAC +0.8 pts

Bears penalties, every game · Chargers penalties, every game · All teams, 2023

When it happened

Chargers’ chance of winning

As low as 47% 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 Bears were.
#WhenWhat happenedWin probability forNext drive
1 Q1 13:28 The Bears were stopped on 3rd & 113rd & 4th downs · 26% expected +8% LAC CHI: Punt
2 Q1 11:32 The Chargers converted 3rd & 53rd & 4th downs · 42% expected +4% LAC LAC: Touchdown
3 Q1 6:32 Illegal Use of Hands on the Bears, 10 yards, wiping out the playJudgment calls +6% LAC LAC: Touchdown
4 Q1 6:08 K. Blasingame dropped a catchable passDrops · 0 drops on 4 catchable balls before this +2% LAC CHI: Punt
5 Q1 5:17 Fair Catch Interference on the Bears (Velus Jones Jr.), 15 yardsJudgment calls · 0 flags in 399 snaps before, position avg 1 per 420 +3% LAC LAC: Touchdown
6 Q2 13:42 The Bears fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +4% CHI CHI: Turnover
7 Q2 12:50 The Bears were stopped on 3rd & 83rd & 4th downs · 32% expectedThe Bears threw an interception-worthy pass, and it was pickedInterceptions · 48% expected to stay out of the defense's hands +6% LAC CHI: Touchdown
8 Q3 12:37 Defensive Offside on the Bears (Andrew Billings), 5 yards, wiping out the playPre-snap flags · 5 flags in 1577 snaps before, position avg 1 per 316 +3% LAC LAC: 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.

  • Corey Linsley (LAC C), out (IR) · 0.7 pts
  • Mike Williams (LAC WR), out (IR) · 0.7 pts
  • Gerald Everett (LAC TE), out · 0.5 pts
  • Braxton Jones (CHI T), out (IR) · 0.7 pts
  • Nate Davis (CHI G), out · 0.4 pts
  • Jaquan Brisker (CHI SS), out · 0.4 pts
  • Terell Smith (CHI CB), out · 0.3 pts
  • Khalil Herbert (CHI RB), out (IR) · 0.1 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

Bears 12% · Chargers 88%

Final margin
Chargers by 17
Luck in points
9.1 for the Chargers
Luck-adjusted margin
Chargers by 7.9
Replay with same day's form
Bears 37% · Chargers 63% 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 8 2023 games · Bears · Chargers

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