luckadjusted

Week 4 2020 · October 4, 2020

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

Saints at Lions, Week 4 2020: who deserved to win?

The Saints beat the Lions 35–29 and were the better team on the day: replayed with the same form, they win 6 of 10.

Before kickoff the Saints were 59% favorites. The biggest swing (Q1, 13:27 left): the Lions converted 3rd & 9, worth 15 points of win probability to the Lions.

Final

New Orleans Saints 35
Detroit Lions 29

October 4, 2020 · Ford Field · Closing line: Saints −3

Luck index +36 Saints lucky · −36 Lions

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. Saints win 6, Lions win 4.

  1. 1 NO 33 DET 10
  2. 2 NO 19 DET 3
  3. 3 NO 24 DET 13
  4. 4 NO 38 DET 30
  5. 5 NO 26 DET 20
  6. 6 NO 21 DET 19
  7. 7 NO 24 DET 27
  8. 8 NO 10 DET 17
  9. 9 NO 20 DET 30
  10. 10 NO 16 DET 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

Saints win 64% of them, Lions 36%, counting the 2% still level after regulation as half each. The line is what actually happened: Saints by 6.

Show as a table
Final margin in the replaysShare of replays
Saints by 17+15.6%
Saints by 9–1620.7%
Saints by 1–827.4%
Level after regulation2.2%
Lions by 1–821.6%
Lions by 9–168.9%
Lions by 17+3.6%

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 +4.3 points to the Lions: the final margin was Saints by 6, without the luck Saints by 10.3. Luck shares are the fitted ones (how much of each kind is luck).

Penalties: Saints 4 for 67 yards, Lions 5 for 49 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
Q2 8:44 Defensive Pass Interference on the Saints (Marcus Williams), 29 yards +7% DET +1.8 pts
Q2 2:00 Unsportsmanlike Conduct on the Lions (Danny Amendola), 14 yards +4% NO +1.4 pts
Q2 0:56 Roughing the Passer on the Lions (Trey Flowers), 15 yards +5% NO +1.5 pts
Q3 7:40 Offensive Holding on the Lions (Marvin Jones), 10 yards +1% NO +1.0 pts
Q3 4:44 Defensive Pass Interference on the Saints (Alex Anzalone), 32 yards +2% DET +2.6 pts
Q3 4:38 Defensive Offside on the Saints (Sheldon Rankins), 1 yard · pre-snap 0% DET 0.0 pts
Q4 5:50 False Start on the Lions, 5 yards · pre-snap +1% NO +0.7 pts
Q4 4:44 Illegal Contact on the Saints (Alex Anzalone), 5 yards, wiping out the play +6% DET +4.3 pts
Q4 3:40 Illegal Formation on the Lions (Tracy Walker), 5 yards · pre-snap +3% NO +0.5 pts

Saints penalties, every game · Lions penalties, every game · All teams, 2020

When it happened

Lions’ chance of winning

As low as 0% and as high as 84%. 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 Lions were ahead in it, below while the Saints were.
#WhenWhat happenedWin probability forNext drive
1 Q1 14:44 The Lions converted 3rd & 103rd & 4th downs · 25% expected +7% DET DET: Touchdown
2 Q1 13:27 The Lions converted 3rd & 93rd & 4th downs · 27% expected +15% DET DET: Touchdown
3 Q1 10:29 The Lions converted 3rd & 73rd & 4th downs · 32% expected +7% DET DET: Touchdown
4 Q1 3:13 The Saints converted 3rd & 33rd & 4th downs · 44% expected +7% NO NO: Touchdown
5 Q2 12:01 The Saints converted 4th & 43rd & 4th downs · 46% expected +11% NO NO: Touchdown
6 Q2 8:44 Defensive Pass Interference on the Saints (Marcus Williams), 29 yardsJudgment calls · 4 flags in 1262 snaps before, position avg 1 per 510 +7% DET DET: Turnover
7 Q2 7:04 The Saints converted 3rd & 13rd & 4th downs · 75% expected +7% NO NO: Touchdown
8 Q2 2:00 The Lions were stopped on 3rd & 63rd & 4th downs · 35% expectedUnsportsmanlike Conduct on the Lions (Danny Amendola), 14 yardsJudgment calls · 1 flag in 772 snaps before, position avg 1 per 385 +11% NO DET: 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.

  • Justin Coleman (DET CB), out (IR) · 0.4 pts
  • Joe Dahl (DET G), out (IR) · 0.2 pts
  • Michael Thomas (NO WR), out · 1.3 pts
  • Marshon Lattimore (NO CB), out · 1.0 pts
  • Andrus Peat (NO G), out · 0.4 pts
  • Andrus Peat (NO G/T), out · 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

Saints 87% · Lions 13%

Final margin
Saints by 6
Luck in points
4.3 for the Lions
Luck-adjusted margin
Saints by 10.3
Replay with same day's form
Saints 64% · Lions 36% 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 · Saints · Lions

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