luckadjusted

Week 17 2023 · December 31, 2023

49ers at Commanders, Week 17 2023: who deserved to win?

The 49ers beat the Commanders 27–10, and it was no fluke: replayed with the way both teams actually played, the 49ers win 10 of 10.

Before kickoff the 49ers were 85% favorites. The biggest swing (Q4, 14:57 left): the Commanders were stopped on 3rd & 8, worth 19 points of win probability to the 49ers.

Final

San Francisco 49ers 27
Washington Commanders 10

December 31, 2023 · FedExField · Closing line: 49ers −14

Luck index +2 49ers about even · −2 Commanders

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 10, Commanders win 0.

  1. 1 SF 37 WAS 3
  2. 2 SF 35 WAS 7
  3. 3 SF 31 WAS 7
  4. 4 SF 27 WAS 6
  5. 5 SF 24 WAS 6
  6. 6 SF 34 WAS 20
  7. 7 SF 30 WAS 17
  8. 8 SF 30 WAS 21
  9. 9 SF 26 WAS 20
  10. 10 SF 9 WAS 6

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 98% of them, Commanders 2%, counting the 1% still level after regulation as half each. The line is what actually happened: 49ers by 17.

Show as a table
Final margin in the replaysShare of replays
49ers by 17+74.1%
49ers by 9–1616.9%
49ers by 1–86.3%
Level after regulation0.7%
Commanders by 1–81.8%
Commanders by 9–160.3%
Commanders by 17+0.1%

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 +6.6 points to the 49ers: the final margin was 49ers by 17, without the luck 49ers by 10.4. 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, 38 yds made · 89% expected
  • J. Slye, 47 yds made · 75% expected
  • J. Moody, 22 yds made · 99% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: 49ers 3 for 20 yards, Commanders 5 for 40 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
Q1 10:29 Defensive Holding on the Commanders (Tariq Castro-Fields), 5 yards +2% SF +0.4 pts
Q1 7:25 False Start on the Commanders, 5 yards · pre-snap +4% SF +0.8 pts
Q2 9:51 Defensive Offside on the 49ers (Javon Hargrave), 5 yards · pre-snap +1% WAS +0.4 pts
Q3 8:51 Face Mask on the Commanders (Cody Barton), 15 yards +4% SF +1.5 pts
Q3 4:26 Illegal Use of Hands on the Commanders, 10 yards, wiping out the play +5% SF +1.9 pts
Q3 1:05 False Start on the Commanders, 5 yards · pre-snap +2% SF +0.5 pts
Q3 0:44 Illegal Contact on the 49ers (Logan Ryan), 5 yards +3% WAS +0.6 pts
Q4 10:38 Offensive Holding on the 49ers (Ronnie Bell), 10 yards +1% WAS +0.9 pts

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

When it happened

Commanders’ chance of winning

As low as 0% and as high as 57%. 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 Commanders were ahead in it, below while the 49ers were.
#WhenWhat happenedWin probability forNext drive
1 Q1 4:19 The 49ers converted 3rd & 93rd & 4th downs · 33% expected +6% SF SF: Touchdown
2 Q2 7:27 The Commanders converted 3rd & 23rd & 4th downs · 58% expected +8% WAS WAS: Touchdown
3 Q2 4:37 The Commanders converted 3rd & 33rd & 4th downs · 41% expected +9% WAS WAS: Touchdown
4 Q2 0:27 The 49ers were stopped on 3rd & 43rd & 4th downs · 41% expected +6% WAS SF: Field goal
5 Q3 13:41 The Commanders were stopped on 3rd & 13rd & 4th downs · 72% expected +9% SF WAS: Punt
6 Q3 4:30 A. Gibson dropped a catchable passDrops · 4 drops on 96 catchable balls before this +6% SF WAS: Turnover
7 Q4 15:00 A. Gibson dropped a catchable passDrops · 5 drops on 98 catchable balls before this +6% SF WAS: Turnover
8 Q4 14:57 The Commanders were stopped on 3rd & 83rd & 4th downs · 29% expectedThe Commanders threw an interception-worthy pass, and it was pickedInterceptions · 49% expected to stay out of the defense's hands +19% SF WAS: Turnover

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.

  • Kendall Fuller (WAS CB), out · 0.8 pts
  • Andrew Wylie (WAS T), out · 0.6 pts
  • Benjamin St-Juste (WAS CB), out · 0.5 pts
  • Tyler Larsen (WAS C), out (IR) · 0.4 pts
  • Jamin Davis (WAS LB), out (IR) · 0.3 pts
  • Percy Butler (WAS FS), out (IR) · 0.3 pts
  • Talanoa Hufanga (SF SS), out (IR) · 0.6 pts
  • Aaron Banks (SF G), out · 0.4 pts
  • Ji'Ayir Brown (SF SS), out · 0.4 pts
  • Arik Armstead (SF DT), 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

49ers 99% · Commanders 1%

Final margin
49ers by 17
Luck in points
6.6 for the 49ers
Luck-adjusted margin
49ers by 10.4
Replay with same day's form
49ers 98% · Commanders 2% 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 17 2023 games · 49ers · Commanders

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