luckadjusted

Week 2 2021 · September 19, 2021

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

Bengals at Bears, Week 2 2021: who deserved to win?

The Bears beat the Bengals 20–17, but the Bengals played well enough to win it: they take 6 of 10 replays with the same day's form. Luck ran their way: fumble bounces alone were worth 3.1 points to the Bears.

Before kickoff the Bears were 56% favorites. The biggest swing (Q4, 11:07 left): Return touchdown by the Bears, worth 28 points of win probability to the Bears.

Final

Cincinnati Bengals 17
Chicago Bears 20

September 19, 2021 · Soldier Field · Closing line: Bears −2

Luck index +63 Bears very lucky · −63 Bengals

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. Bengals win 6, Bears win 4.

  1. 1 CIN 26 CHI 3
  2. 2 CIN 16 CHI 0
  3. 3 CIN 11 CHI 0
  4. 4 CIN 19 CHI 10
  5. 5 CIN 15 CHI 10
  6. 6 CIN 16 CHI 14
  7. 7 CIN 18 CHI 20
  8. 8 CIN 7 CHI 13
  9. 9 CIN 3 CHI 13
  10. 10 CIN 5 CHI 23

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

Bengals win 63% of them, Bears 37%, counting the 3% still level after regulation as half each. The line is what actually happened: Bears by 3.

Show as a table
Final margin in the replaysShare of replays
Bengals by 17+13.4%
Bengals by 9–1618.6%
Bengals by 1–828.4%
Level after regulation2.9%
Bears by 1–820.1%
Bears by 9–1611.7%
Bears by 17+4.9%

Where the luck was

Take the luck out

The final margin was Bears by 3. Remove the luck, one kind at a time, and it becomes Bears by 2.3.

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.

  • E. McPherson, 53 yds made · 70% expected
  • C. Santos, 28 yds made · 97% expected
  • C. Santos, 22 yds made · 99% 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 50% 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 Bengals were.
#WhenWhat happenedWin probability forNext drive
1 Q1 14:17 The Bears converted 3rd & 83rd & 4th downs · 28% expected +8% CHI CHI: Touchdown
2 Q1 11:30 Defensive Pass Interference on the Bengals (Eli Apple), 32 yardsJudgment calls · 9 flags in 1065 snaps before, position avg 1 per 213 +14% CHI CHI: Touchdown
3 Q2 4:12 The Bengals converted 3rd & 113rd & 4th downs · 22% expected +6% CIN CIN: Punt
4 Q3 5:01 The Bengals fumbled and the Bears recoveredFumble bounces · loose balls are close to 50/50 +7% CHI CIN: Opp touchdown
5 Q3 3:03 The Bears converted 3rd & 133rd & 4th downs · 20% expected +7% CHI CHI: Field goal
6 Q4 11:07 The Bengals were stopped on 3rd & 33rd & 4th downs · 47% expectedReturn touchdown by the BearsSpecial teams +28% CHI CIN: Turnover
7 Q4 3:50 The Bears were stopped on 3rd & 73rd & 4th downs · 31% expected +13% CIN CHI: End of game
8 Q4 2:55 The Bears converted 3rd & 93rd & 4th downs · 26% expected +13% 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.

  • Danny Trevathan (CHI LB), out (IR) · 0.3 pts
  • Fred Johnson (CIN OT), out · 0.2 pts
  • Darius Phillips (CIN DB), out · 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

Bengals 35% · Bears 65%

Final margin
Bears by 3
Luck in points
0.7 for the Bears
Luck-adjusted margin
Bears by 2.3
Replay with same day's form
Bengals 63% · Bears 37% 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 2 2021 games · Bengals · Bears

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