luckadjusted

Week 3 2020 · September 27, 2020

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

Bears at Falcons, Week 3 2020: who deserved to win?

The Bears stole one. They beat the Falcons 30–26, but replayed with the way both teams actually played, the Falcons win 8 of 10. Luck ran their way: injuries alone were worth 3.2 points to the Bears.

Before kickoff the Falcons were 57% favorites. The biggest swing (Q4, 2:00 left): the Bears converted 3rd & 8, worth 28 points of win probability to the Bears.

Final

Chicago Bears 30
Atlanta Falcons 26

September 27, 2020 · Mercedes-Benz Stadium · Closing line: Falcons −2.5

Luck index +82 Bears very lucky · −82 Falcons

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 2, Falcons win 8.

  1. 1 CHI 38 ATL 23
  2. 2 CHI 40 ATL 36
  3. 3 CHI 9 ATL 12
  4. 4 CHI 43 ATL 48
  5. 5 CHI 19 ATL 27
  6. 6 CHI 23 ATL 34
  7. 7 CHI 20 ATL 35
  8. 8 CHI 10 ATL 28
  9. 9 CHI 6 ATL 30
  10. 10 CHI 10 ATL 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

Bears win 18% of them, Falcons 82%, counting the 2% still level after regulation as half each. The line is what actually happened: Bears by 4.

Show as a table
Final margin in the replaysShare of replays
Bears by 17+2.5%
Bears by 9–164.9%
Bears by 1–810.5%
Level after regulation1.6%
Falcons by 1–818.5%
Falcons by 9–1621.5%
Falcons by 17+40.5%

Where the luck was

Take the luck out

The final margin was Bears by 4. Remove the luck, one kind at a time, and it becomes Bears by 1.4.

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.

  • C. Santos, 46 yds missed · 77% expected
  • C. Santos, 35 yds made · 92% expected
  • Y. Koo, 29 yds made · 97% expected
  • Y. Koo, 36 yds made · 93% expected
  • Y. Koo, 48 yds missed · 79% expected
  • Extra point missed · 93% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Falcons’ chance of winning

As low as 0% and as high as 99%. 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 Falcons were ahead in it, below while the Bears were.
#WhenWhat happenedWin probability forNext drive
1 Q1 10:57 C. Santos missed 46-yard field goalKicks · 77% expected for him, 3 of 7 from 45+ before +9% ATL CHI: Field goal
2 Q1 6:18 Offensive Holding on the Bears, 10 yards, wiping out the playJudgment calls +7% ATL ATL: Punt
3 Q2 5:13 Roughing the Passer on the Bears (Mario Edwards), 15 yards, wiping out the playJudgment calls · 1 flag in 365 snaps before, position avg 1 per 259 +9% ATL ATL: Touchdown
4 Q2 4:48 The Falcons converted 3rd & 53rd & 4th downs · 42% expected +8% ATL ATL: Touchdown
5 Q4 4:15 The Falcons were stopped on 3rd & 153rd & 4th downs · 22% expectedFalse Start on the Falcons (Calvin Ridley), 5 yardsPre-snap flags · 4 flags in 845 snaps before, position avg 1 per 385 +8% CHI ATL: Punt
6 Q4 4:10 Unnecessary Roughness on the Falcons, 15 yardsJudgment calls +10% CHI CHI: Touchdown
7 Q4 2:00 The Bears converted 3rd & 83rd & 4th downs · 32% expected +28% CHI CHI: Touchdown
8 Q4 1:14 Unsportsmanlike Conduct on the Falcons (Damontae Kazee), 15 yardsJudgment calls · 2 flags in 1065 snaps before, position avg 1 per 510 +11% CHI CHI: 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.

  • Julio Jones (ATL WR), out · 1.3 pts
  • Kaleb McGary (ATL T), out · 1.2 pts
  • Kendall Sheffield (ATL CB), out · 0.4 pts
  • Ricardo Allen (ATL SS), 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

Bears 75% · Falcons 25%

Final margin
Bears by 4
Luck in points
2.6 for the Bears
Luck-adjusted margin
Bears by 1.4
Replay with same day's form
Bears 18% · Falcons 82% 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 3 2020 games · Bears · Falcons

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