luckadjusted
CFB Week 4 · 2026

Week 8 2025 · October 18, 2025

Utah at BYU, Week 8 2025: who deserved to win?

BYU beat Utah 24–21, but the replays call it close to a coin flip: with the way both teams played, BYU wins 4 of 10.

Before kickoff Utah was a 60% favorite. The biggest swing (Q3, 4:33 left): Holding on Utah, 10 yards, wiping out the play, worth 18 points of win probability to BYU.

Final

Utah Utes 21
BYU Cougars 24

October 18, 2025 · LaVell Edwards Stadium · Closing line: Utah −4

Luck index +57 BYU lucky · −57 Utah

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. Utah wins 6, BYU wins 4.

  1. 1 UTAH 52 BYU 24
  2. 2 UTAH 24 BYU 3
  3. 3 UTAH 31 BYU 17
  4. 4 UTAH 41 BYU 30
  5. 5 UTAH 28 BYU 21
  6. 6 UTAH 30 BYU 27
  7. 7 UTAH 17 BYU 20
  8. 8 UTAH 24 BYU 31
  9. 9 UTAH 28 BYU 41
  10. 10 UTAH 35 BYU 56

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

Utah wins 57% of them, BYU 43%, counting the 3% still level after regulation as half each. The line is what actually happened: BYU by 3.

Show as a table
Final margin in the replaysShare of replays
Utah by 17+18.8%
Utah by 9–1617.4%
Utah by 1–818.9%
Level after regulation2.7%
BYU by 1–821.3%
BYU by 9–1611.1%
BYU by 17+9.7%

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 +1.8 points to Utah: the final margin was BYU by 3, without the luck BYU by 4.8. Luck shares are the fitted ones (how much of each kind is luck).

Penalties: Utah 9 for 58 yards, BYU 5 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 12:22 False Start on Utah, 3 yards · pre-snap +1% BYU +0.5 pts
Q1 2:19 Intentional Grounding on Utah, 10 yards +5% BYU +2.3 pts
Q2 15:00 Delay of Game on Utah, 5 yards · pre-snap +2% BYU +0.8 pts
Q2 4:17 False Start on Utah, 5 yards · pre-snap +2% BYU +0.7 pts
Q3 14:56 Holding on Utah, 10 yards +7% UTAH +2.6 pts
Q3 4:55 Holding on BYU, 10 yards +3% UTAH +1.1 pts
Q3 4:33 Holding on Utah, 10 yards, wiping out the play +18% BYU +5.1 pts
Q3 1:43 Pass Interference on BYU, 8 yards +10% UTAH +2.7 pts
Q3 0:00 Delay of Game on Utah, 5 yards · pre-snap +3% BYU +0.7 pts
Q4 6:37 False Start on BYU, 5 yards · pre-snap +1% UTAH +0.5 pts
Q4 3:12 Illegal Substitution on Utah, 5 yards · pre-snap 0% BYU +0.2 pts
Q4 1:54 Pass Interference on BYU, 15 yards +1% UTAH +0.6 pts
Q4 1:28 Pass Interference on BYU, 4 yards +7% UTAH +2.6 pts
Q4 0:27 Delay of Game on Utah, 5 yards · pre-snap 0% BYU +1.4 pts

When it happened

BYU’s chance of winning

As low as 30% 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 Utah was.
#WhenWhat happenedWin probability forNext drive
1 Q2 4:54 Utah converted 3rd & 93rd & 4th downs · 30% expected +7% UTAH UTAH: Touchdown
2 Q3 14:56 Holding on Utah, 10 yardsJudgment calls +7% UTAH BYU: Punt
3 Q3 11:40 Utah converted 3rd & 153rd & 4th downs · 21% expectedUtah fumbled and recovered itFumble bounces · loose balls are close to 50/50 +15% UTAH UTAH: Turnover on downs
4 Q3 4:33 Holding on Utah, 10 yards, wiping out the playJudgment calls +18% BYU BYU: Punt
5 Q3 1:43 Pass Interference on BYU, 8 yardsJudgment calls +10% UTAH UTAH: Touchdown
6 Q4 7:21 BYU converted 3rd & 43rd & 4th downs · 48% expected +8% BYU BYU: Touchdown
7 Q4 4:22 BYU converted 3rd & 113rd & 4th downs · 26% expected +8% BYU BYU: Turnover on downs
8 Q4 1:28 Pass Interference on BYU, 4 yardsJudgment calls +7% UTAH UTAH: Touchdown

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

Utah 24% · BYU 76%

Final margin
BYU by 3
Luck in points
1.8 for Utah
Luck-adjusted margin
BYU by 4.8
Replay with same day's form
Utah 57% · BYU 43% 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 8 2025 games · Utah · BYU

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