luckadjusted

Week 17 2021 · January 2, 2022

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

Texans at 49ers, Week 17 2021: who deserved to win?

The 49ers beat the Texans 23–7, and it was no fluke: replayed with the way both teams actually played, the 49ers win 10 of 10. The Texans had the bounces: injuries alone were worth 7.4 points to the Texans.

Before kickoff the 49ers were 85% favorites. The biggest swing (Q3, 0:20 left): Offensive Holding on the Texans (Pharaoh Brown), 10 yards, wiping out the play, worth 26 points of win probability to the 49ers.

Final

Houston Texans 7
San Francisco 49ers 23

January 2, 2022 · Levi's Stadium · Closing line: 49ers −14

Luck index +1 49ers about even · −1 Texans

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. Texans win 0, 49ers win 10.

  1. 1 HOU 20 SF 23
  2. 2 HOU 17 SF 26
  3. 3 HOU 28 SF 40
  4. 4 HOU 12 SF 27
  5. 5 HOU 17 SF 34
  6. 6 HOU 20 SF 41
  7. 7 HOU 10 SF 34
  8. 8 HOU 6 SF 33
  9. 9 HOU 13 SF 44
  10. 10 HOU 10 SF 51

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

Texans win 1% of them, 49ers 99%. The line is what actually happened: 49ers by 16.

Show as a table
Final margin in the replaysShare of replays
Texans by 17+0.1%
Texans by 9–160.2%
Texans by 1–80.8%
Level after regulation0.1%
49ers by 1–83.6%
49ers by 9–1611.1%
49ers by 17+84.1%

Where the luck was

Take the luck out

The final margin was 49ers by 16. Remove the luck, one kind at a time, and it becomes 49ers by 23.4.

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.

  • R. Gould, 37 yds made · 90% expected
  • K. Fairbairn, 45 yds missed · 77% expected
  • R. Gould, 27 yds made · 97% expected
  • R. Gould, 36 yds made · 91% 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 Texans were.
#WhenWhat happenedWin probability forNext drive
1 Q2 5:27 The Texans converted 3rd & 33rd & 4th downs · 50% expected +11% HOU HOU: Touchdown
2 Q3 13:34 The 49ers converted 3rd & 63rd & 4th downs · 37% expected +13% SF SF: Turnover on downs
3 Q3 8:21 The Texans were stopped on 3rd & 33rd & 4th downs · 50% expected +12% SF HOU: Punt
4 Q3 8:14 Defensive Pass Interference on the Texans (Terrance Mitchell), 37 yardsJudgment calls · 3 flags in 2367 snaps before, position avg 1 per 213 +13% SF SF: Touchdown
5 Q3 0:20 Offensive Holding on the Texans (Pharaoh Brown), 10 yards, wiping out the playJudgment calls · 17 flags in 1291 snaps before, position avg 1 per 269 +26% SF SF: Touchdown
6 Q4 14:23 Defensive Pass Interference on the 49ers (Josh Norman), 33 yardsJudgment calls · 12 flags in 1815 snaps before, position avg 1 per 213 +15% HOU HOU: Missed field goal
7 Q4 12:50 The Texans were stopped on 3rd & 33rd & 4th downs · 50% expected +13% SF HOU: Missed field goal
8 Q4 12:08 K. Fairbairn missed 45-yard field goalKicks · 77% expected for him, 15 of 26 from 45+ before +12% SF HOU: 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.

  • Jimmy Garoppolo (SF QB), out, replaced by t.lance · 7.3 pts
  • Emmanuel Moseley (SF CB), out (IR) · 0.6 pts
  • Talanoa Hufanga (SF SS), out · 0.4 pts
  • Azeez Al-Shaair (SF LB), out · 0.3 pts
  • Tytus Howard (HOU T), out (IR) · 0.8 pts
  • Maliek Collins (HOU DT), out · 0.4 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

Texans 2% · 49ers 98%

Final margin
49ers by 16
Luck in points
7.5 for the Texans
Luck-adjusted margin
49ers by 23.5
Replay with same day's form
Texans 1% · 49ers 99% 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 17 2021 games · Texans · 49ers

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