One really important factor is the grading curve, if used. At my university, I think the goal was to give the average student 60%, or a mid 2.1) with some formula for test score adjustment to compensate for particularly tough papers. The idea is that your score ends up representing your ability with respect to the cohort and the specific tests that you were given. https://warwick.ac.uk/fac/sci/physics/current/teach/g…
This posts sums up everything that's wrong with grading and modern colleges.
That is generally hard to measure and frankly there is little accountability for bad courses. At the worst end you have bad profs who are proud of high failure rates because they don't understand it as a failure to teach but as a seal of quality how rigorous their standards are complex the subject matter is that they are teaching.
Not that grading on a curve solves any of that, but it eases the burden on students.