luckadjusted

Week 2 2024 · September 12, 2024

Bills at Dolphins, Week 2 2024: who deserved to win?

The Bills beat the Dolphins 31–10 and were the better team on the day: replayed with the same form, they win 7 of 10. The Dolphins had the bounces: kicks alone were worth 2.9 points to the Dolphins.

Before kickoff the Dolphins were 57% favorites. The biggest swing (Q1, 12:26 left): the Dolphins were stopped on 3rd & 13, worth 16 points of win probability to the Bills.

Final

Buffalo Bills 31
Miami Dolphins 10

September 12, 2024 · Hard Rock Stadium · Closing line: Dolphins −2.5

Luck index +33 Bills lucky · −33 Dolphins

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. Bills win 7, Dolphins win 3.

  1. 1 BUF 44 MIA 20
  2. 2 BUF 34 MIA 17
  3. 3 BUF 26 MIA 13
  4. 4 BUF 20 MIA 10
  5. 5 BUF 30 MIA 23
  6. 6 BUF 20 MIA 16
  7. 7 BUF 14 MIA 13
  8. 8 BUF 24 MIA 27
  9. 9 BUF 20 MIA 27
  10. 10 BUF 17 MIA 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

Bills win 67% of them, Dolphins 33%, counting the 2% still level after regulation as half each. The line is what actually happened: Bills by 21.

Show as a table
Final margin in the replaysShare of replays
Bills by 17+18.3%
Bills by 9–1620.4%
Bills by 1–826.5%
Level after regulation2.2%
Dolphins by 1–819.2%
Dolphins by 9–168.8%
Dolphins by 17+4.7%

Where the luck was

Take the luck out

The final margin was Bills by 21. Remove the luck, one kind at a time, and it becomes Bills by 18.3.

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.

  • T. Bass, 43 yds made · 83% expected
  • J. Sanders, 34 yds made · 94% expected
  • T. Bass, 45 yds missed · 82% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Dolphins’ 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 Dolphins were ahead in it, below while the Bills were.
#WhenWhat happenedWin probability forNext drive
1 Q1 12:26 The Dolphins were stopped on 3rd & 133rd & 4th downs · 23% expectedThe Dolphins threw an interception-worthy pass, and it was pickedInterceptions · 50% expected to stay out of the defense's hands +16% BUF MIA: Touchdown
2 Q1 9:55 The Bills converted 4th & 33rd & 4th downs · 54% expected +11% BUF BUF: Touchdown
3 Q1 5:03 The Dolphins converted 3rd & 43rd & 4th downs · 45% expected +8% MIA MIA: Touchdown
4 Q2 14:22 The Bills converted 3rd & 53rd & 4th downs · 43% expected +7% BUF BUF: Field goal
5 Q2 12:06 Offensive Holding on the Dolphins, 10 yards, wiping out the playJudgment calls +8% BUF BUF: Touchdown
6 Q2 7:11 The Bills converted 3rd & 123rd & 4th downs · 27% expected +8% BUF BUF: Touchdown
7 Q2 3:50 The Dolphins were stopped on 4th & 23rd & 4th downs · 60% expected +6% BUF MIA: Field goal
8 Q3 9:37 The Dolphins were stopped on 3rd & 53rd & 4th downs · 41% expectedThe Dolphins threw an interception-worthy pass, and it was pickedInterceptions · 51% expected to stay out of the defense's handsReturn touchdown by the BillsSpecial teams +14% BUF MIA: Turnover on downs

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.

  • Bradley Chubb (MIA LB), out (IR) · 0.4 pts
  • Taron Johnson (BUF CB), out · 0.8 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

Bills 100% · Dolphins 0%

Final margin
Bills by 21
Luck in points
2.7 for the Bills
Luck-adjusted margin
Bills by 18.3
Replay with same day's form
Bills 67% · Dolphins 33% 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 2 2024 games · Bills · Dolphins

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