luckadjusted
CFB Week 4 · 2026

Week 4 2026 · September 26, 2026

Iowa at Michigan, Week 4 2026: who deserved to win?

Iowa beat Michigan 20–19, a result the replays rarely give: with the way both teams actually played, Michigan wins 9 of 10. Luck ran its way: 3rd & 4th downs alone were worth 11 points of win probability to Iowa.

Before kickoff Michigan was a 61% favorite. The biggest swing (Q4, 2:52 left): False Start on Iowa, 5 yards, worth 10 points of win probability to Michigan.

Final

Iowa Hawkeyes 20
Michigan Wolverines 19

September 26, 2026 · Michigan Stadium · Closing line: Michigan −4.5

Luck index +87 Iowa very lucky · −87 Michigan

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. Iowa wins 1, Michigan wins 9.

  1. 1 IOWA 6 MICH 0
  2. 2 IOWA 14 MICH 17
  3. 3 IOWA 13 MICH 17
  4. 4 IOWA 17 MICH 24
  5. 5 IOWA 7 MICH 17
  6. 6 IOWA 24 MICH 38
  7. 7 IOWA 7 MICH 24
  8. 8 IOWA 10 MICH 30
  9. 9 IOWA 7 MICH 31
  10. 10 IOWA 0 MICH 31

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

Iowa wins 13% of them, Michigan 87%, counting the 4% still level after regulation as half each. The line is what actually happened: Iowa by 1.

Show as a table
Final margin in the replaysShare of replays
Iowa by 17+1.1%
Iowa by 9–163.1%
Iowa by 1–88.4%
Level after regulation4.3%
Michigan by 1–822.1%
Michigan by 9–1622.4%
Michigan by 17+38.6%

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 +0.5 points to Iowa: the final margin was Iowa by 1, without the luck Iowa by 0.5. Luck shares are the fitted ones (how much of each kind is luck).

The kicks

How likely each kicker was to make that kick (his own record, the distance), and what happened.

  • T. Butkowski, 41 yds made · 71% expected
  • T. Butkowski, 22 yds made · 94% expected
  • C. Buhr, 51 yds missed · 53% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Iowa 5 for 34 yards, Michigan 5 for 45 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 7:43 False Start on Michigan, 5 yards · pre-snap +2% IOWA +1.2 pts
Q1 7:18 Holding on Michigan, 10 yards +4% IOWA +2.0 pts
Q2 14:50 Personal Foul on Iowa, 15 yards +3% MICH +1.6 pts
Q3 12:03 Holding on Michigan, 10 yards +3% IOWA +1.5 pts
Q3 9:00 Holding on Iowa, 6 yards +1% MICH +0.4 pts
Q3 8:18 False Start on Iowa, 3 yards · pre-snap +2% MICH +0.5 pts
Q4 5:59 Illegal Formation on Michigan, 5 yards · pre-snap +4% IOWA +1.2 pts
Q4 2:52 False Start on Iowa, 5 yards · pre-snap +10% MICH +1.7 pts
Q4 0:28 False Start on Iowa, 5 yards · pre-snap +2% MICH +0.4 pts
Q4 0:26 Unnecessary Roughness on Michigan, 15 yards +7% IOWA +1.3 pts

When it happened

Michigan’s chance of winning

As low as 0% and as high as 95%. 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 Michigan was ahead in it, below while Iowa was.
#WhenWhat happenedWin probability forNext drive
1 Q2 3:17 Michigan was stopped on 4th & 13rd & 4th downs · 77% expected +8% IOWA MICH: Punt
2 Q3 0:37 Iowa converted 3rd & 53rd & 4th downs · 40% expected +7% IOWA IOWA: Touchdown
3 Q4 14:42 Iowa converted 3rd & 93rd & 4th downs · 27% expected +10% IOWA IOWA: Touchdown
4 Q4 9:34 Iowa converted 3rd & 33rd & 4th downs · 53% expected +6% IOWA IOWA: Punt
5 Q4 3:23 Iowa was stopped on 3rd & 33rd & 4th downs · 53% expected +6% MICH IOWA: Missed field goal
6 Q4 2:52 False Start on Iowa, 5 yardsPre-snap flags +10% MICH MICH: Punt
7 Q4 2:33 C. Buhr missed a 51-yard field goalKicks · 53% expected for him, 2 of 3 from 45+ before +7% MICH IOWA: Touchdown
8 Q4 0:26 Unnecessary Roughness on Michigan, 15 yardsJudgment calls +7% IOWA IOWA: 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

Iowa 52% · Michigan 48%

Final margin
Iowa by 1
Luck in points
0.5 for Iowa
Luck-adjusted margin
Iowa by 0.5
Replay with same day's form
Iowa 13% · Michigan 87% 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 4 2026 games · Iowa · Michigan

More from Week 4 2026

Every week 4 game, 2026