luckadjusted

Week 10 2019 · November 10, 2019

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

Lions at Bears, Week 10 2019: who deserved to win?

The Bears stole one. They beat the Lions 20–13, but replayed with the way both teams actually played, the Lions win 9 of 10. Luck ran their way: injuries alone were worth 6.5 points to the Bears.

The Bears won on an off day: they played far below what the matchup promised. In a fresh game against the Lions they would win 70% of the time; with this day’s form, 14%. The numbers

Before kickoff the Bears were 67% favorites. The biggest swing (Q1, 10:57 left): the Lions converted 3rd & 8, worth 13 points of win probability to the Lions.

Final

Detroit Lions 13
Chicago Bears 20

November 10, 2019 · Soldier Field · Closing line: Bears −6

Luck index +86 Bears very lucky · −86 Lions

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. Lions win 9, Bears win 1.

  1. 1 DET 40 CHI 9
  2. 2 DET 26 CHI 3
  3. 3 DET 33 CHI 14
  4. 4 DET 33 CHI 17
  5. 5 DET 30 CHI 16
  6. 6 DET 17 CHI 6
  7. 7 DET 15 CHI 7
  8. 8 DET 22 CHI 16
  9. 9 DET 39 CHI 36
  10. 10 DET 3 CHI 12

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.

The Bears won on an off day

They played far below what the matchup promised. In a fresh game against the Lions they would win 70% of the time; with this day’s form, 14%.

56 points apart for the Bears: the gap is how differently this game went from what the two teams usually are.

UnitThis gameUsual levelBetter or worse than usual
Lions offenseEPA per play gained −0.11 +0.12 worse by 0.23
Lions defenseEPA per play allowed +0.04 +0.13 better by 0.09
Bears offenseEPA per play gained +0.04 +0.09 worse by 0.06
Bears defenseEPA per play allowed −0.11 +0.05 better by 0.15

EPA (expected points added) per play on competitive snaps, turnovers left out because they are valued as luck. Usual level: the team’s earlier games this season plus half of last season, pulled toward the league average. One team’s defense and the other team’s offense are the same snaps, so one game can’t fully say whose day it was; it shows how far this one was from both teams’ norms.

How 4,000 replays ended

Lions win 86% of them, Bears 14%, counting the 2% still level after regulation as half each. The line is what actually happened: Bears by 7.

Show as a table
Final margin in the replaysShare of replays
Lions by 17+43.3%
Lions by 9–1622.8%
Lions by 1–819.1%
Level after regulation1.5%
Bears by 1–88.9%
Bears by 9–163.4%
Bears by 17+1.0%

Where the luck was

Take the luck out

The final margin was Bears by 7. Remove the luck, one kind at a time, and it becomes Lions by 0.5.

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.

  • M. Prater, 22 yds made · 99% expected
  • M. Prater, 54 yds made · 62% expected
  • Extra point missed · 93% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Bears’ chance of winning

As low as 33% 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 Bears were ahead in it, below while the Lions were.
#WhenWhat happenedWin probability forNext drive
1 Q1 10:57 The Lions converted 3rd & 83rd & 4th downs · 31% expected +13% DET DET: Field goal
2 Q3 14:52 The Bears fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +8% CHI CHI: Touchdown
3 Q3 12:36 Defensive Pass Interference on the Lions (Darius Slay), 22 yardsJudgment calls · 3 flags in 352 snaps before, position avg 1 per 199 +7% CHI CHI: Touchdown
4 Q3 11:05 The Lions were stopped on 3rd & 23rd & 4th downs · 60% expected +9% CHI DET: Punt
5 Q3 9:44 The Bears converted 3rd & 93rd & 4th downs · 29% expected +8% CHI CHI: Touchdown
6 Q4 2:25 Offensive Pass Interference on the Lions (Kenny Golladay), 10 yards, wiping out the playJudgment calls · 0 flags in 467 snaps before, position avg 1 per 331 +7% CHI CHI: Punt
7 Q4 2:18 The Lions were stopped on 4th & 113rd & 4th downs · 25% expected +8% CHI DET: Turnover on downs
8 Q4 0:07 The Lions were stopped on 4th & 73rd & 4th downs · 33% expected +8% CHI –

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.

  • Kyle Long (CHI G), out (IR) · 0.5 pts
  • Akiem Hicks (CHI DT), out (IR) · 0.4 pts
  • Matthew Stafford (DET QB), out, replaced by j.driskel · 6.3 pts
  • Romeo Okwara (DET DE), out · 0.4 pts
  • Tracy Walker (DET FS), out · 0.3 pts
  • Da'Shawn Hand (DET DE), out · 0.2 pts
  • Kerryon Johnson (DET RB), out (IR) · 0.2 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

Lions 19% · Bears 81%

Final margin
Bears by 7
Luck in points
7.5 for the Bears
Luck-adjusted margin
Lions by 0.5
Replay with same day's form
Lions 86% · Bears 14% 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 10 2019 games · Lions · Bears

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