I had a highschool calculus teacher who was very explicit about designing their tests on an A/B/C system.

The idea was that the A section was the basic plug-n-chug versions of the problem that everyone should be able to get if you were even half paying attention in class; the B section is stuff that requires a bit more reasoning and analysis, and may have a pitfall or two, but they'll be things that were at least mentioned; and the C section is effectively extra credit— a problem where you needed to have a deeper understanding in order to figure out something novel about it, or like you needed to re-derive something from first principles in a way that was slightly different from what was shown in class, that kind of thing.

And the sections weren't equally weighted; I think it was usually like 50/30/20, or even 60/30/10.

Some people hated this, but I really liked how explicit it was. There was no mystery meat— the whole evaluation scheme was very open about its design and intent.

Depends on country, university and professor. In Germany, the general rule is that grading on a curve isn't allowed or at least strongly discouraged. There was a short while when such a system was acceptable, called ECTS grades (not to be confused with ECTS credits), but that was done away with in a year or so. Currently, grades are based on the lecture contents and the expectation of the lecturer for the progress a student should make. Lecturers are relatively free to do whatever they please within those bounds. If a test ends in everybody failing, tough luck, maybe next time. If that unfortunate event does repeat too often, the dean might get involved, but can't do a lot more than talk to the lecturer.

Not strictly curve grading, but when I was studying electronics one of the professors had a 9-step algorithm for processing raw scores into grades. That involved normalizing the lab scores between different reviewers (so that harshness of a particular reviewer would be compensated for). He also assigned `cos(percentage_from_other_test as radians)` instead of resits if you missed one of the tests for valid reason but had shown up on the other.

On one hand I really like the former approach and could understand the latter (organizing resits is likely a huge PITA). On the other that's the only professor I heard of that was attacked with an axe by one of his students.

> only professor I heard of that was attacked

How did that end, if it's not too weird to ask

> normalizing the lab scores between different reviewers

Sounds like a good idea to me :-)

From my experience... it varies widely. The university will have a standard, the department will, the professor will.

I had experience taking undergraduate courses at 4 institutions in the USA and of course many departments.

I had some professors that expected the grades to fall like grade school did with 90-100 % being a high percentage. Others gave 4-6 difficult multi part problems and graded on a transparent curve. Others gave difficult problems and were not transparent about the grading scheme.

If school is using grading curves that school has already failed and there is no saving it before grading system changes.