I think it was 2018 that Purdue upset Ohio St.
It was and if you cherry-pick down to the 19 years from 2000-2018 the Purdue/Ohio State thing becomes even weirder. In those 19 years, Purdue's record against B1G teams and ND:
- .688 Illinois, 11-5
- .632 Indiana, 12-7
- .500 Minnesota, 8-8
- .438 Northwestern, 7-9
- .385 Ohio State, 5-8
- .375 Iowa, 6-10
- .333 Nebraska, 2-4
- .308 Michigan State, 4-9
- .250 Michigan, 3-9
- .200 Notre Dame, 3-12
- .182 Penn State, 2-9
- .133 Wisconsin, 2-13
- .000 Maryland, 0-2
- .000 Rutgers, 0-1
Ohio State's record against B1G teams from 2000-2018:
- 1.00 Indiana, 16-0
- 1.00 Rutgers, 5-0
- 1.00 Maryland, 5-0
- .917 Minnesota, 11-1
- .909 Northwestern, 10-1
- .867 Illinois, 13-2
- .842 Michigan, 16-3
- .800 Michigan State, 12-3
- .800 Nebraska, 4-1
- .778 Iowa, 7-2
- .737 Penn State, 14-5
- .733 Wisconsin, 11-4
- .615 Purdue, 8-5
Ohio State's record against Purdue from 2000-2018 suggests that the Buckeyes were a bottom-half team in the league over that time.
Purdue's record against Ohio State from 2000-2018 suggests that the Boilermakers were easily the second best team in the B1G over that time.
Neither of those things are true. Why the anomaly?
The first reason, I would submit, is scheduling. Purdue had unsurprising wins over mediocre Ohio State teams in 2000, 2004, and 2011. Ohio State only had four seasons with more than three losses over the 19 seasons from 2000-2018. Purdue played Ohio State in all four of those seasons and won three of the games. The only other B1G teams to play tOSU in all four of those seasons were Michigan (2-2), Penn State (2-2), and Wisconsin (2-2). The six Ohio State teams that Purdue missed from 2000-2018 were:
- 10-2 B1G co-Champ in 2005
- 12-1 B1G Champ and BCSNCG Participant in 2006
- 14-1 B1G and National Champ in 2014
- 12-1 in 2015
- 11-2 CFP Participant in 2016
- 12-2 B1G Champ in 2017
Statistically, Purdue should have missed at least one of the mediocre tOSU teams and instead played at least one of the above teams that they more-than-likely would have lost to.
The second reason, I would submit, is that Purdue took advantage of the opportunities that the schedule gave them. Note that Michigan, Penn State, and Wisconsin also played all four of the mediocre tOSU teams from 2000-2018 but each of them only went 2-2 where Purdue went 3-1.
The third reason is the crazy upsets. Purdue's wins over Ohio State in 2009 and 2018 are just crazy upsets. You can't seriously argue that the Purdue teams that went 5-7 and 6-7 were actually better than the tOSU teams that went 11-2 and 13-1 but at the right time, in the right place, those Purdue teams managed to be the better team for the right 60 minutes.
The fourth reason, I would submit, is that the sample size isn't all that big so a few bounces makes a big difference. Purdue had the 29 point blowout in 2018 but their other four wins were by one score each:
- 3 points in 2011
- 4 points in 2000
- 7 points in 2004
- 8 points in 2009
If you switch two of those games from PU to tOSU then tOSU's record against PU moves to 10th on the list above, right between Iowa and Penn State. Purdue's record against Ohio State moves to 10th, right between Michigan and Notre Dame.