luckadjusted

Week 1 2023 · September 10, 2023

49ers at Steelers, Week 1 2023: who deserved to win?

The 49ers beat the Steelers 30–7 and were the better team on the day: replayed with the same form, they win 7 of 10. The Steelers had the bounces: judgment calls alone were worth 2.7 points to the Steelers.

Before kickoff the 49ers were 54% favorites. The biggest swing (Q1, 11:34 left): the 49ers converted 4th & 1, worth 11 points of win probability to the 49ers.

Final

San Francisco 49ers 30
Pittsburgh Steelers 7

September 10, 2023 · Acrisure Stadium · Closing line: 49ers −1.5

Luck index +30 49ers lucky · −30 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. 49ers win 7, Steelers win 3.

  1. 1 SF 45 PIT 19
  2. 2 SF 24 PIT 6
  3. 3 SF 29 PIT 15
  4. 4 SF 24 PIT 13
  5. 5 SF 31 PIT 23
  6. 6 SF 15 PIT 10
  7. 7 SF 19 PIT 17
  8. 8 SF 10 PIT 13
  9. 9 SF 13 PIT 22
  10. 10 SF 6 PIT 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

49ers win 70% of them, Steelers 30%, counting the 4% still level after regulation as half each. The line is what actually happened: 49ers by 23.

Show as a table
Final margin in the replaysShare of replays
49ers by 17+24.8%
49ers by 9–1620.3%
49ers by 1–823.2%
Level after regulation3.8%
Steelers by 1–815.0%
Steelers by 9–169.0%
Steelers by 17+4.0%

Where the luck was

Take the luck out

The final margin was 49ers by 23. Remove the luck, one kind at a time, and it becomes 49ers by 21.0.

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.

  • J. Moody, 41 yds made · 85% expected
  • J. Moody, 32 yds made · 95% expected
  • J. Moody, 40 yds made · 87% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Steelers’ chance of winning

As low as 0% and as high as 55%. 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 Steelers were ahead in it, below while the 49ers were.
#WhenWhat happenedWin probability forNext drive
1 Q1 14:02 The Steelers were stopped on 3rd & 53rd & 4th downs · 40% expected +7% SF PIT: Punt
2 Q1 12:09 The 49ers were stopped on 3rd & 13rd & 4th downs · 74% expected +4% PIT SF: Touchdown
3 Q1 11:34 The 49ers converted 4th & 13rd & 4th downs · 74% expected +11% SF SF: Touchdown
4 Q1 8:08 The Steelers were stopped on 3rd & 53rd & 4th downs · 40% expectedThe Steelers threw an interception-worthy pass, and it was pickedInterceptions · 48% expected to stay out of the defense's hands +11% SF PIT: Punt
5 Q1 5:32 The 49ers were stopped on 3rd & 143rd & 4th downs · 23% expected +3% PIT SF: Field goal
6 Q1 4:48 Defensive Offside on the Steelers (Patrick Peterson), 5 yards, wiping out the playPre-snap flags · 24 flags in 4149 snaps before, position avg 1 per 216 +3% PIT SF: Field goal
7 Q1 3:05 The 49ers fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +4% SF SF: Touchdown
8 Q1 2:01 The 49ers got away with an interception-worthy throwInterceptions · 48% expected to stay out of the defense's hands +4% SF SF: Touchdown

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

49ers 100% · Steelers 0%

Final margin
49ers by 23
Luck in points
2.0 for the 49ers
Luck-adjusted margin
49ers by 21.0
Replay with same day's form
49ers 70% · Steelers 30% 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 1 2023 games · 49ers · Steelers

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