This is not considered backbiting if the need arises, and in some cases, it is necessary in order for the best interests of the students to be established and any harms to be averted. This is similar to what scholars dd in the field of jarh’ wa-t-ta’deel, the science of upholding and criticising narrators of hadeeth, because the Sunnah was not preserved except through criticising those that deserved to be criticised, so that people were not misguided by their narrations, and those that were not allowed to be narrated from. Scholars classified narrators into categories of weak, liars etc., etc. This is not backbiting and, rather, it is from the obligation of giving sincere advice. The same can be said regarding a student about whom teachers discuss whether or not to keep him or expel him, since he might have a negative impact on other students, in which case it is in the best interests of everyone if he is removed. All of this is not considered backbiting. Allaah knows best.
Is it considered backbiting when teachers discuss the strong and weak points of a student and his abilities, and whether he should remain or expelled from school?