luckadjusted

Week 5 2020 · October 11, 2020

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

Dolphins at 49ers, Week 5 2020: who deserved to win?

The Dolphins beat the 49ers 43–17, and it was no fluke: replayed with the way both teams actually played, the Dolphins win 9 of 10. The 49ers had the bounces: judgment calls alone were worth 3.7 points to the 49ers.

An off day for the 49ers: their offense and defense both played far below their usual level. In a fresh game against the Dolphins they would win 56% of the time; with this day’s form, 15%. The numbers

Before kickoff the 49ers were 74% favorites.

Final

Miami Dolphins 43
San Francisco 49ers 17

October 11, 2020 · Levi's Stadium · Closing line: 49ers −8.5

Luck index +15 Dolphins about even · −15 49ers

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. Dolphins win 9, 49ers win 1.

  1. 1 MIA 50 SF 14
  2. 2 MIA 43 SF 17
  3. 3 MIA 34 SF 14
  4. 4 MIA 30 SF 13
  5. 5 MIA 29 SF 16
  6. 6 MIA 30 SF 20
  7. 7 MIA 31 SF 24
  8. 8 MIA 22 SF 17
  9. 9 MIA 29 SF 27
  10. 10 MIA 26 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.

An off day for the 49ers

Their offense and defense both played far below their usual level. In a fresh game against the Dolphins they would win 56% of the time; with this day’s form, 15%.

41 points apart for the 49ers: the gap is how differently this game went from what the two teams usually are.

UnitThis gameUsual levelBetter or worse than usual
Dolphins offenseEPA per play gained +0.51 +0.08 better by 0.43
Dolphins defenseEPA per play allowed −0.18 +0.18 better by 0.35
49ers offenseEPA per play gained −0.18 +0.17 worse by 0.35
49ers defenseEPA per play allowed +0.51 +0.04 worse by 0.47

EPA (expected points added) per play on competitive snaps, turnovers left out because they are valued as luck. Usual level: the team’s earlier games this season plus half of last season, pulled toward the league average. One team’s defense and the other team’s offense are the same snaps, so one game can’t fully say whose day it was; it shows how far this one was from both teams’ norms.

How 4,000 replays ended

Dolphins win 85% of them, 49ers 15%, counting the 1% still level after regulation as half each. The line is what actually happened: Dolphins by 26.

Show as a table
Final margin in the replaysShare of replays
Dolphins by 17+41.4%
Dolphins by 9–1623.1%
Dolphins by 1–819.6%
Level after regulation1.4%
49ers by 1–89.3%
49ers by 9–163.8%
49ers by 17+1.4%

Where the luck was

Take the luck out

The final margin was Dolphins by 26. Remove the luck, one kind at a time, and it becomes Dolphins by 18.9.

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. Sanders, 26 yds made · 98% expected
  • J. Sanders, 50 yds made · 70% expected
  • J. Sanders, 29 yds made · 97% expected
  • R. Gould, 37 yds made · 90% expected
  • J. Sanders, 31 yds made · 96% expected
  • J. Sanders, 49 yds made · 73% 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 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 49ers were ahead in it, below while the Dolphins were.
#WhenWhat happenedWin probability forNext drive
1 Q1 13:54 The 49ers were stopped on 3rd & 53rd & 4th downs · 42% expected +5% MIA SF: Punt
2 Q1 12:30 The Dolphins converted 3rd & 113rd & 4th downs · 27% expected +7% MIA MIA: Touchdown
3 Q1 10:23 The 49ers converted 3rd & 33rd & 4th downs · 52% expected +3% SF SF: Turnover on downs
4 Q1 7:40 The 49ers were stopped on 4th & 13rd & 4th downs · 74% expected +5% MIA SF: Punt
5 Q1 0:49 The Dolphins fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50False Start on the 49ers (Ross Dwelley), 5 yardsPre-snap flags · 1 flag in 718 snaps before, position avg 1 per 276 +5% MIA MIA: Punt
6 Q2 8:49 Clipping on the Dolphins, 15 yardsJudgment calls +3% SF SF: Punt
7 Q2 7:35 The Dolphins converted 3rd & 223rd & 4th downs · 17% expected +7% MIA MIA: Touchdown
8 Q2 5:41 The 49ers fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +3% SF SF: 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.

  • Richard Sherman (SF CB), out (IR) · 1.6 pts
  • Nick Bosa (SF DE), out (IR) · 1.1 pts
  • Emmanuel Moseley (SF CB), out · 0.6 pts
  • K'Waun Williams (SF CB), out (IR) · 0.4 pts
  • Dontae Johnson (SF CB), out · 0.3 pts
  • Dee Ford (SF LB), out (IR) · 0.1 pts
  • Austin Jackson (MIA T), out (IR) · 0.6 pts
  • Shaq Lawson (MIA DE), out · 0.4 pts
  • Vince Biegel (MIA LB), out (IR) · 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

Dolphins 100% · 49ers 0%

Final margin
Dolphins by 26
Luck in points
7.1 for the Dolphins
Luck-adjusted margin
Dolphins by 18.9
Replay with same day's form
Dolphins 85% · 49ers 15% 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 5 2020 games · Dolphins · 49ers

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