luckadjusted

Week 3 2023 · September 21, 2023

Giants at 49ers, Week 3 2023: who deserved to win?

The 49ers beat the Giants 30–12, and it was no fluke: replayed with the way both teams actually played, the 49ers win 9 of 10.

Before kickoff the 49ers were 78% favorites. The biggest swing (Q1, 11:32 left): the 49ers converted 3rd & 8, worth 13 points of win probability to the 49ers.

Final

New York Giants 12
San Francisco 49ers 30

September 21, 2023 · Levi's Stadium · Closing line: 49ers −10.5

Luck index +9 49ers about even · −9 Giants

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. Giants win 1, 49ers win 9.

  1. 1 NYG 30 SF 24
  2. 2 NYG 19 SF 21
  3. 3 NYG 21 SF 27
  4. 4 NYG 0 SF 7
  5. 5 NYG 13 SF 23
  6. 6 NYG 13 SF 26
  7. 7 NYG 3 SF 20
  8. 8 NYG 21 SF 41
  9. 9 NYG 3 SF 27
  10. 10 NYG 3 SF 33

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

Giants win 9% of them, 49ers 91%, counting the 2% still level after regulation as half each. The line is what actually happened: 49ers by 18.

Show as a table
Final margin in the replaysShare of replays
Giants by 17+0.7%
Giants by 9–161.6%
Giants by 1–86.7%
Level after regulation1.7%
49ers by 1–819.3%
49ers by 9–1623.3%
49ers by 17+46.8%

Where the luck was

What the luck was worth

Every lucky and unlucky play, weighted by the moment it happened: its swing in win probability, added up by kind. A missed kick in a decided game counts for nothing; the same kick at the end of a tie game can be most of a win.

Swings add up across a game, so in one that went back and forth they can pass 100%. On the scoreboard the same luck was worth +4.8 points to the 49ers: the final margin was 49ers by 18, without the luck 49ers by 13.2. Luck shares are the fitted ones (how much of each kind 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, 28 yds made · 97% expected
  • G. Gano, 44 yds made · 80% expected
  • G. Gano, 57 yds made · 61% expected
  • J. Moody, 21 yds made · 99% expected
  • J. Moody, 36 yds made · 91% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Giants 6 for 37 yards, 49ers 6 for 71 yards

Every accepted flag, in order, and what it did to the helped team’s chance of winning at that moment, including any play it wiped out (points on the scoreboard in grey). A flag in a decided game is worth nothing; one at the turn of a close game can be worth most of a win. Judgment calls count toward luck, pre-snap fouls mostly don’t. How calls are valued

WhenFlagWin probability for
Q2 14:09 Ineligible Downfield Pass on the 49ers, 5 yards, wiping out the play +4% NYG +1.4 pts
Q2 2:00 Offensive Holding on the 49ers, 10 yards +1% NYG +0.9 pts
Q2 1:51 Roughing the Passer on the Giants (Leonard Williams), 5 yards +2% SF +0.7 pts
Q3 12:24 Offensive Holding on the 49ers, 4 yards 0% NYG +0.4 pts
Q3 10:56 Fair Catch Interference on the 49ers (Shemar Jean-Charles), 15 yards 0% NYG +1.5 pts
Q3 10:11 Defensive Pass Interference on the 49ers (Deommodore Lenoir), 22 yards +3% NYG +1.4 pts
Q3 7:42 Defensive Holding on the Giants (Darnay Holmes), 5 yards +3% SF +0.9 pts
Q3 5:02 Illegal Contact on the Giants (Kayvon Thibodeaux), 5 yards +3% SF +1.5 pts
Q3 3:23 False Start on the Giants (Daniel Bellinger), 5 yards · pre-snap +1% SF +0.6 pts
Q4 15:00 Defensive Holding on the Giants (Tre Hawkins), 5 yards 0% SF +0.3 pts
Q4 12:47 Face Mask on the Giants, 12 yards, wiping out the play +4% SF +2.1 pts
Q4 5:53 Unnecessary Roughness on the 49ers (Dre Greenlaw), 15 yards 0% NYG +1.2 pts

Giants penalties, every game · 49ers penalties, every game · All teams, 2023

When it happened

49ers’ chance of winning

As low as 48% 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 Giants were.
#WhenWhat happenedWin probability forNext drive
1 Q1 14:18 The 49ers converted 3rd & 63rd & 4th downs · 37% expected +6% SF SF: Field goal
2 Q1 11:32 The 49ers converted 3rd & 83rd & 4th downs · 32% expected +13% SF SF: Field goal
3 Q1 8:05 The Giants converted 3rd & 43rd & 4th downs · 45% expected +5% NYG NYG: Field goal
4 Q1 6:27 The Giants converted 3rd & 13rd & 4th downs · 73% expected +5% NYG NYG: Field goal
5 Q1 4:44 G. Brightwell dropped a catchable passDrops · 0 drops on 9 catchable balls before this +5% SF NYG: Field goal
6 Q2 13:48 The 49ers converted 3rd & 153rd & 4th downs · 21% expected +10% SF SF: Touchdown
7 Q2 10:17 The 49ers converted 3rd & 133rd & 4th downs · 24% expected +9% SF SF: Touchdown
8 Q2 6:59 The Giants were stopped on 3rd & 23rd & 4th downs · 60% expected +5% SF NYG: Punt

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.

  • Brandon Aiyuk (SF WR), out · 1.5 pts
  • Andrew Thomas (NYG T), out · 0.9 pts
  • Saquon Barkley (NYG RB), out · 0.6 pts
  • Jarrad Davis (NYG LB), out (IR) · 0.3 pts
  • Ben Bredeson (NYG G), 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

Giants 1% · 49ers 99%

Final margin
49ers by 18
Luck in points
4.8 for the 49ers
Luck-adjusted margin
49ers by 13.2
Replay with same day's form
Giants 9% · 49ers 91% 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 3 2023 games · Giants · 49ers

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