luckadjusted

Week 17 2021 · January 2, 2022

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

Cardinals at Cowboys, Week 17 2021: who deserved to win?

The Cardinals beat the Cowboys 25–22 and were the better team on the day: replayed with the same form, they win 8 of 10. The Cowboys had the bounces: injuries alone were worth 3.5 points to the Cowboys.

An off day for the Cowboys: they played far below what the matchup promised. In a fresh game against the Cardinals they would win 65% of the time; with this day’s form, 25%. The numbers

Before kickoff the Cowboys were 68% favorites. The biggest swing (Q1, 9:26 left): the Cardinals converted 3rd & 9, worth 14 points of win probability to the Cardinals.

Final

Arizona Cardinals 25
Dallas Cowboys 22

January 2, 2022 · AT&T Stadium · Closing line: Cowboys −6.5

Luck index +25 Cardinals about even · −25 Cowboys

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. Cardinals win 8, Cowboys win 2.

  1. 1 ARI 37 DAL 7
  2. 2 ARI 27 DAL 7
  3. 3 ARI 47 DAL 31
  4. 4 ARI 23 DAL 10
  5. 5 ARI 20 DAL 10
  6. 6 ARI 24 DAL 17
  7. 7 ARI 14 DAL 10
  8. 8 ARI 23 DAL 21
  9. 9 ARI 19 DAL 23
  10. 10 ARI 7 DAL 20

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 Cowboys

They played far below what the matchup promised. In a fresh game against the Cardinals they would win 65% of the time; with this day’s form, 25%.

40 points apart for the Cowboys: the gap is how differently this game went from what the two teams usually are.

UnitThis gameUsual levelBetter or worse than usual
Cardinals offenseEPA per play gained +0.19 +0.16 better by 0.02
Cardinals defenseEPA per play allowed +0.16 +0.11 worse by 0.05
Cowboys offenseEPA per play gained +0.16 +0.13 better by 0.03
Cowboys defenseEPA per play allowed +0.19 +0.11 worse by 0.08

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

Cardinals win 75% of them, Cowboys 25%, counting the 3% still level after regulation as half each. The line is what actually happened: Cardinals by 3.

Show as a table
Final margin in the replaysShare of replays
Cardinals by 17+27.3%
Cardinals by 9–1620.9%
Cardinals by 1–826.8%
Level after regulation2.7%
Cowboys by 1–813.5%
Cowboys by 9–166.8%
Cowboys by 17+2.0%

Where the luck was

Take the luck out

The final margin was Cardinals by 3. Remove the luck, one kind at a time, and it becomes Cowboys by 2.0.

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.

  • M. Prater, 24 yds made · 98% expected
  • G. Zuerlein, 43 yds missed · 84% expected
  • M. Prater, 53 yds made · 68% expected
  • M. Prater, 26 yds made · 97% expected
  • M. Prater, 38 yds made · 90% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Cowboys’ chance of winning

As low as 0% and as high as 58%. 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 Cowboys were ahead in it, below while the Cardinals were.
#WhenWhat happenedWin probability forNext drive
1 Q1 9:26 The Cardinals converted 3rd & 93rd & 4th downs · 30% expected +14% ARI ARI: Field goal
2 Q1 4:11 The Cowboys converted 4th & 23rd & 4th downs · 59% expected +12% DAL DAL: Missed field goal
3 Q1 2:39 G. Zuerlein missed 43-yard field goalKicks · 84% expected for him +11% ARI DAL: Punt
4 Q2 15:00 Offensive Holding on the Cowboys, 10 yards, wiping out the playJudgment calls +9% ARI ARI: Touchdown
5 Q2 10:33 The Cardinals converted 4th & 23rd & 4th downs · 61% expected +8% ARI ARI: Touchdown
6 Q2 5:32 The Cardinals converted 4th & 13rd & 4th downs · 67% expected +8% ARI ARI: Touchdown
7 Q2 2:00 Defensive Pass Interference on the Cardinals, 5 yards, wiping out the playJudgment calls +13% DAL DAL: Touchdown
8 Q2 1:30 The Cowboys converted 3rd & 53rd & 4th downs · 39% expected +8% DAL DAL: Touchdown

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.

  • Keanu Neal (DAL LB), out (IR) · 0.2 pts
  • DeAndre Hopkins (ARI WR), out (IR) · 1.0 pts
  • D.J. Humphries (ARI T), out (IR) · 0.7 pts
  • Marco Wilson (ARI CB), out · 0.5 pts
  • James Conner (ARI RB), out · 0.4 pts
  • Robert Alford (ARI CB), out (IR) · 0.4 pts
  • Jordan Phillips (ARI DE), out · 0.3 pts
  • Markus Golden (ARI LB), out (IR) · 0.2 pts
  • Sean Harlow (ARI G), 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

Cardinals 26% · Cowboys 74%

Final margin
Cardinals by 3
Luck in points
5.0 for the Cardinals
Luck-adjusted margin
Cowboys by 2.0
Replay with same day's form
Cardinals 75% · Cowboys 25% 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 17 2021 games · Cardinals · Cowboys

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