luckadjusted

Week 3 2019 · September 22, 2019

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

Steelers at 49ers, Week 3 2019: who deserved to win?

The 49ers beat the Steelers 24–20, and it was no fluke: replayed with the way both teams actually played, the 49ers win 9 of 10. The Steelers had the bounces: fumble bounces alone were worth 3.1 points to the Steelers.

Before kickoff the 49ers were 67% favorites. The biggest swing (Q4, 6:53 left): the 49ers were stopped on 3rd & 7, worth 45 points of win probability to the Steelers.

Final

Pittsburgh Steelers 20
San Francisco 49ers 24

September 22, 2019 · Levi's Stadium · Closing line: 49ers −6

Luck index +13 49ers about even · −13 Steelers

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. Steelers win 1, 49ers win 9.

  1. 1 PIT 28 SF 20
  2. 2 PIT 19 SF 22
  3. 3 PIT 18 SF 24
  4. 4 PIT 23 SF 32
  5. 5 PIT 8 SF 19
  6. 6 PIT 20 SF 34
  7. 7 PIT 10 SF 26
  8. 8 PIT 6 SF 27
  9. 9 PIT 9 SF 33
  10. 10 PIT 10 SF 45

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

Steelers win 13% of them, 49ers 87%, counting the 2% still level after regulation as half each. The line is what actually happened: 49ers by 4.

Show as a table
Final margin in the replaysShare of replays
Steelers by 17+1.1%
Steelers by 9–163.1%
Steelers by 1–87.5%
Level after regulation1.6%
49ers by 1–817.2%
49ers by 9–1620.7%
49ers by 17+48.9%

Where the luck was

Take the luck out

The final margin was 49ers by 4. Remove the luck, one kind at a time, and it becomes 49ers by 7.1.

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. Boswell, 46 yds made · 80% expected
  • C. Boswell, 26 yds made · 98% expected
  • R. Gould, 24 yds made · 98% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

49ers’ chance of winning

As low as 27% 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 49ers were ahead in it, below while the Steelers were.
#WhenWhat happenedWin probability forNext drive
1 Q3 11:23 The 49ers converted 3rd & 83rd & 4th downs · 31% expected +11% SF SF: Touchdown
2 Q3 5:54 The Steelers converted 3rd & 43rd & 4th downs · 41% expected +28% PIT PIT: Touchdown
3 Q4 10:34 Defensive Pass Interference on the 49ers (Jason Verrett), 32 yardsJudgment calls · no snap history yet +8% PIT PIT: Touchdown
4 Q4 6:53 The 49ers were stopped on 3rd & 73rd & 4th downs · 26% expectedThe 49ers fumbled and the Steelers recoveredFumble bounces · loose balls are close to 50/50 +45% PIT SF: Touchdown
5 Q4 5:36 The Steelers fumbled and the 49ers recoveredFumble bounces · loose balls are close to 50/50 +17% SF PIT: Turnover on downs
6 Q4 2:53 Offensive Holding on the 49ers, 10 yardsJudgment calls +14% PIT PIT: Turnover on downs
7 Q4 2:08 Defensive Holding on the Steelers (Mark Barron), 5 yardsJudgment calls · 0 flags in 126 snaps before, position avg 1 per 393 +13% SF SF: Touchdown
8 Q4 0:51 The Steelers were stopped on 3rd & 33rd & 4th downs · 48% expectedThe Steelers fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +10% PIT PIT: Turnover on downs

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.

  • Joe Staley (SF T), out · 1.1 pts
  • Sean Davis (PIT FS), out (IR) · 0.4 pts
  • Vince Williams (PIT LB), 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

Steelers 16% · 49ers 84%

Final margin
49ers by 4
Luck in points
3.1 for the Steelers
Luck-adjusted margin
49ers by 7.1
Replay with same day's form
Steelers 13% · 49ers 87% 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 2019 games · Steelers · 49ers

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