luckadjusted

Week 15 2020 · December 20, 2020

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

Eagles at Cardinals, Week 15 2020: who deserved to win?

The Cardinals beat the Eagles 33–26, and it was no fluke: replayed with the way both teams actually played, the Cardinals win 8 of 10. The Eagles had the bounces: fumble bounces alone were worth 4.7 points to the Eagles.

Before kickoff the Cardinals were 68% favorites. The biggest swing (Q4, 4:07 left): the Eagles converted 3rd & 12, worth 17 points of win probability to the Eagles.

Final

Philadelphia Eagles 26
Arizona Cardinals 33

December 20, 2020 · State Farm Stadium · Closing line: Cardinals −6.5

Luck index +15 Cardinals about even · −15 Eagles

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 2, Cardinals win 8.

  1. 1 PHI 43 ARI 26
  2. 2 PHI 36 ARI 32
  3. 3 PHI 31 ARI 33
  4. 4 PHI 19 ARI 24
  5. 5 PHI 30 ARI 39
  6. 6 PHI 16 ARI 29
  7. 7 PHI 27 ARI 44
  8. 8 PHI 20 ARI 41
  9. 9 PHI 24 ARI 49
  10. 10 PHI 3 ARI 37

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 15% of them, Cardinals 85%, counting the 2% still level after regulation as half each. The line is what actually happened: Cardinals by 7.

Show as a table
Final margin in the replaysShare of replays
Eagles by 17+1.6%
Eagles by 9–163.9%
Eagles by 1–88.2%
Level after regulation1.8%
Cardinals by 1–817.4%
Cardinals by 9–1619.4%
Cardinals by 17+47.8%

Where the luck was

Take the luck out

The final margin was Cardinals by 7. Remove the luck, one kind at a time, and it becomes Cardinals by 13.9.

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).

When it happened

Cardinals’ chance of winning

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 Cardinals were ahead in it, below while the Eagles were.
#WhenWhat happenedWin probability forNext drive
1 Q1 12:37 Offensive Pass Interference on the Cardinals (Dan Arnold), 10 yards, wiping out the playJudgment calls · 6 flags in 555 snaps before, position avg 1 per 276 +11% PHI PHI: Safety
2 Q2 14:09 The Eagles converted 3rd & 203rd & 4th downs · 17% expected +11% PHI PHI: Touchdown
3 Q2 6:25 The Eagles converted 4th & 33rd & 4th downs · 42% expected +14% PHI PHI: Touchdown
4 Q4 14:56 The Cardinals converted 4th & 23rd & 4th downs · 59% expected +12% ARI ARI: Turnover on downs
5 Q4 9:35 The Cardinals converted 3rd & 83rd & 4th downs · 31% expectedFalse Start on the Cardinals, 5 yardsPre-snap flags +12% ARI ARI: Touchdown
6 Q4 7:24 The Cardinals converted 3rd & 23rd & 4th downs · 60% expected +16% ARI ARI: Touchdown
7 Q4 4:07 The Eagles converted 3rd & 123rd & 4th downs · 24% expected +17% PHI PHI: Turnover on downs
8 Q4 1:55 The Eagles were stopped on 4th & 213rd & 4th downs · 17% expected +15% ARI PHI: End of game

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 Pugh (ARI OL), out · 0.5 pts
  • Corey Peters (ARI DL), out (IR) · 0.4 pts
  • Jalen Thompson (ARI S), out · 0.4 pts
  • Zane Gonzalez (ARI K), out (IR) · 0.3 pts
  • Darius Slay (PHI CB), out · 1.0 pts
  • Lane Johnson (PHI T), out (IR) · 0.9 pts
  • Jason Peters (PHI T), out (IR) · 0.6 pts
  • Rodney McLeod (PHI S), out (IR) · 0.4 pts
  • Avonte Maddox (PHI CB), out (IR) · 0.4 pts
  • Nathan Gerry (PHI LB), 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 1% · Cardinals 99%

Final margin
Cardinals by 7
Luck in points
6.9 for the Eagles
Luck-adjusted margin
Cardinals by 13.9
Replay with same day's form
Eagles 15% · Cardinals 85% 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 15 2020 games · Eagles · Cardinals

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