luckadjusted
CFB Week 4 · 2026

Week 2 2026 · September 12, 2026

Arizona at BYU, Week 2 2026: who deserved to win?

BYU beat Arizona 28–17, and the replays back it up: with the way both teams actually played, BYU wins 8 of 10.

Before kickoff BYU was a 66% favorite. The biggest swing (Q4, 10:36 left): Arizona converted 3rd & 12, worth 13 points of win probability to Arizona.

Final

Arizona Wildcats 17
BYU Cougars 28

September 12, 2026 · LaVell Edwards Stadium · Closing line: BYU −6.5

Luck index +18 BYU about even · −18 Arizona

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. Arizona wins 2, BYU wins 8.

  1. 1 ARIZ 14 BYU 3
  2. 2 ARIZ 24 BYU 21
  3. 3 ARIZ 21 BYU 24
  4. 4 ARIZ 26 BYU 31
  5. 5 ARIZ 21 BYU 30
  6. 6 ARIZ 10 BYU 21
  7. 7 ARIZ 0 BYU 14
  8. 8 ARIZ 14 BYU 34
  9. 9 ARIZ 3 BYU 28
  10. 10 ARIZ 7 BYU 42

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, conversion and judgment call redrawn; everything else fixed. The narrowest view of luck.

How 4,000 replays ended

Arizona wins 18% of them, BYU 82%, counting the 4% still level after regulation as half each. The line is what actually happened: BYU by 11.

Show as a table
Final margin in the replaysShare of replays
Arizona by 17+1.8%
Arizona by 9–164.2%
Arizona by 1–811.8%
Level after regulation3.9%
BYU by 1–822.5%
BYU by 9–1620.0%
BYU by 17+35.8%

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 +4.2 points to BYU: the final margin was BYU by 11, without the luck BYU by 6.8. Luck shares are the fitted ones (how much of each kind is luck).

Penalties: Arizona 7 for 55 yards, BYU 7 for 59 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 9:09 Holding on BYU, 10 yards +8% ARIZ +3.5 pts
Q1 7:13 Holding on Arizona, 10 yards, wiping out the play +7% BYU +3.3 pts
Q2 3:08 Illegal Formation on Arizona, 5 yards · pre-snap +3% BYU +1.1 pts
Q3 12:31 Holding on BYU, 9 yards +4% ARIZ +1.3 pts
Q3 9:25 Personal Foul on BYU, 15 yards +5% ARIZ +1.6 pts
Q3 8:55 Holding on Arizona, 10 yards +4% BYU +1.6 pts
Q3 6:08 False Start on BYU, 4 yards · pre-snap +2% ARIZ +0.7 pts
Q3 5:39 Delay of Game on BYU, 2 yards · pre-snap +1% ARIZ +0.3 pts
Q3 5:17 Illegal Substitution on Arizona, 5 yards · pre-snap +2% BYU +0.8 pts
Q3 5:00 Holding on BYU, 4 yards, wiping out the play +6% ARIZ +2.0 pts
Q3 3:44 Personal Foul on Arizona, 15 yards +1% BYU +1.9 pts
Q3 1:28 False Start on Arizona, 5 yards · pre-snap +2% BYU +0.7 pts
Q4 12:30 Pass Interference on BYU, 15 yards +6% ARIZ +1.7 pts
Q4 11:32 False Start on Arizona, 5 yards · pre-snap +3% BYU +0.6 pts

When it happened

BYU’s chance of winning

As low as 46% and as high as 100%. Numbers mark the biggest luck moments, listed below.

Our in-game win probability: the score, the value of the possession and the time left, starting from the betting line. Overtime has no clock and is drawn at a fixed width. Shaded above the middle while BYU was ahead in it, below while Arizona was.
#WhenWhat happenedWin probability forNext drive
1 Q1 9:09 Holding on BYU, 10 yardsJudgment calls +7% ARIZ ARIZ: Turnover
2 Q1 7:13 Holding on Arizona, 10 yards, wiping out the playJudgment calls +7% BYU BYU: Touchdown
3 Q2 13:25 BYU converted 3rd & 103rd & 4th downs · 29% expected +6% BYU BYU: Touchdown
4 Q3 10:56 BYU converted 3rd & 73rd & 4th downs · 37% expected +6% BYU BYU: Touchdown
5 Q3 5:00 Holding on BYU, 4 yards, wiping out the playJudgment calls +6% ARIZ ARIZ: Punt
6 Q4 12:30 Pass Interference on BYU, 15 yardsJudgment calls +6% ARIZ ARIZ: Turnover on downs
7 Q4 10:36 Arizona converted 3rd & 123rd & 4th downs · 25% expected +13% ARIZ ARIZ: Turnover on downs
8 Q4 8:24 Arizona was stopped on 4th & 43rd & 4th downs · 49% expected +12% BYU ARIZ: Punt

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

Arizona 8% · BYU 92%

Final margin
BYU by 11
Luck in points
4.2 for BYU
Luck-adjusted margin
BYU by 6.8
Replay with same day's form
Arizona 18% · BYU 82% unchanged: why
How much of each is luck?

0% treats it as skill, 100% as pure luck. The tick is our fit.

What counts

None by default: our tests measured no carryover after a lucky break. Slide it up to count a break for more than its own swing. 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 expected points from CollegeFootballData.com via cfbfastR; win probability from our own model of the score, the possession and the betting line; kicks valued against each kicker’s own record. College play-by-play has no charting of drops or interception-worthy throws and no injury reports, so those kinds of luck aren’t counted here.

Methodology and validation · All Week 2 2026 games · Arizona · BYU

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