luckadjusted

Week 4 2020 · October 4, 2020

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

Eagles at 49ers, Week 4 2020: who deserved to win?

The Eagles stole one. They beat the 49ers 25–20, but replayed with the way both teams actually played, the 49ers win 9 of 10. Luck ran their way: fumble bounces alone were worth 23 points of win probability to the Eagles.

Before kickoff the 49ers were 74% favorites. The biggest swing (Q4, 10:06 left): the 49ers were stopped on 3rd & 10, worth 31 points of win probability to the Eagles.

Final

Philadelphia Eagles 25
San Francisco 49ers 20

October 4, 2020 · Levi's Stadium · Closing line: 49ers −8.5

Luck index +87 Eagles very lucky · −87 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. Eagles win 1, 49ers win 9.

  1. 1 PHI 9 SF 3
  2. 2 PHI 15 SF 17
  3. 3 PHI 16 SF 19
  4. 4 PHI 20 SF 27
  5. 5 PHI 21 SF 31
  6. 6 PHI 14 SF 27
  7. 7 PHI 20 SF 36
  8. 8 PHI 19 SF 38
  9. 9 PHI 10 SF 34
  10. 10 PHI 9 SF 41

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

Eagles win 13% of them, 49ers 87%, counting the 1% still level after regulation as half each. The line is what actually happened: Eagles by 5.

Show as a table
Final margin in the replaysShare of replays
Eagles by 17+0.9%
Eagles by 9–162.9%
Eagles by 1–88.7%
Level after regulation1.4%
49ers by 1–820.4%
49ers by 9–1623.9%
49ers by 17+41.8%

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 +11.4 points to the Eagles: the final margin was Eagles by 5, without the luck 49ers by 6.4. Luck shares are the fitted ones (how much of each kind is luck).

Penalties: Eagles 3 for 25 yards, 49ers 6 for 42 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 11:45 Neutral Zone Infraction on the 49ers (Fred Warner), 5 yards · pre-snap +3% PHI +0.9 pts
Q1 10:12 Offensive Holding on the 49ers, 10 yards +3% PHI +1.2 pts
Q1 6:33 Defensive Pass Interference on the 49ers (Jimmie Ward), 12 yards +6% PHI +2.9 pts
Q1 5:43 Defensive Holding on the 49ers (Kwon Alexander), 5 yards +3% PHI +0.9 pts
Q2 13:29 Face Mask on the Eagles (Nathan Gerry), 15 yards +5% SF +2.5 pts
Q2 7:28 False Start on the Eagles, 5 yards · pre-snap +1% SF +1.1 pts
Q4 7:07 Defensive Holding on the 49ers (Jimmie Ward), 5 yards, wiping out the play +6% SF +0.3 pts
Q4 2:39 Defensive Offside on the Eagles (Josh Sweat), 5 yards · pre-snap 0% SF +0.6 pts
Q4 1:40 False Start on the 49ers, 5 yards · pre-snap +2% PHI +0.2 pts

Eagles penalties, every game · 49ers penalties, every game · All teams, 2020

When it happened

49ers’ chance of winning

As low as 0% and as high as 78%. 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 Eagles were.
#WhenWhat happenedWin probability forNext drive
1 Q1 0:31 The 49ers converted 3rd & 73rd & 4th downs · 33% expected +15% SF SF: Touchdown
2 Q2 4:25 The 49ers converted 3rd & 63rd & 4th downs · 36% expected +11% SF SF: Turnover
3 Q2 1:52 The Eagles fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +8% PHI PHI: Punt
4 Q4 10:06 The 49ers were stopped on 3rd & 103rd & 4th downs · 28% expectedThe 49ers fumbled and the Eagles recoveredFumble bounces · loose balls are close to 50/50 +31% PHI SF: Opp touchdown
5 Q4 8:36 The Eagles converted 4th & 43rd & 4th downs · 44% expected +16% PHI PHI: Touchdown
6 Q4 6:39 The Eagles fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +12% PHI PHI: Touchdown
7 Q4 5:50 Return touchdown by the EaglesSpecial teams +24% PHI PHI: Opp touchdown
8 Q4 0:07 The 49ers were stopped on 4th & 103rd & 4th downs · 27% expected +17% PHI –

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 n.mullens · 4.4 pts
  • Richard Sherman (SF CB), out (IR) · 1.6 pts
  • Nick Bosa (SF DE), out (IR) · 1.1 pts
  • Emmanuel Moseley (SF CB), out · 0.5 pts
  • Dre Greenlaw (SF LB), out · 0.3 pts
  • Ahkello Witherspoon (SF CB), out · 0.3 pts
  • Raheem Mostert (SF RB), out · 0.2 pts
  • Dee Ford (SF LB), out (IR) · 0.1 pts
  • Dallas Goedert (PHI TE), out (IR) · 1.0 pts
  • Jason Peters (PHI T), out (IR) · 0.6 pts
  • DeSean Jackson (PHI WR), out · 0.6 pts
  • Avonte Maddox (PHI CB), out · 0.3 pts
  • Isaac Seumalo (PHI G), out (IR) · 0.3 pts
  • Jalen Reagor (PHI WR), out (IR) · 0.3 pts
  • Jason Peters (PHI G), out (IR) · 0.3 pts
  • Isaac Seumalo (PHI OL), out (IR) · 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

Eagles 40% · 49ers 60%

Final margin
Eagles by 5
Luck in points
11.4 for the Eagles
Luck-adjusted margin
49ers by 6.4
Replay with same day's form
Eagles 13% · 49ers 87% 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 4 2020 games · Eagles · 49ers

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