Lettermarking

In the case of high schools which use a lettermarking system, the letters were transmuted into numbers by means of keys showing equivalent marks .

Source: wiktionary

In reality this kind of lettermarking system is closely related to its predecessors in having a value range which imitates an employer's wage scale for his workers.

Source: wiktionary

In some schools, teachers will go through the negative evolution of lettermarking from the satisfactory-unsatisfactory marking without seeming to be aware of the confusion existing in mixing the philosophies underlying the two systems.

Source: wiktionary