I am interested in different methods for scaling grades from a class test, say. In this case there is only one test and this gives the whole class grade. I remember from years ago a method that took into account the relative strength of the students taking the class by looking at their grades in other classes. However I can't remember the details at all. The idea was that a hard test taken by strong students would be scaled up more than an easy test taken by weak students.
Is anyone familiar with this idea and how it might work mathematically?
In response to comments let me give an example. Say there is an optional class on Semiotics and Structuralism that the strongest students typically choose to take. The mean for this unit is 60% typically, say. Say there is also another optional class on how to spell the words in Harry Potter book one that the weakest students take. Say this gets the same mean of 60% typically. It would be interesting to know what formulas have been used to scale the former class so that the mean is higher than the latter.