The school quality institute of North Rhine-Westphalia, QUA-LiS NRW, publishes a lesson unit that teaches pupils how to give feedback. Its text on feedback starts with a plain rule. Sie betreffen nicht die Persönlichkeit, sondern das Verhalten einer Person. Feedback comments concern not the personality but the behavior of a person.
Whoever gives feedback makes no value judgments and no accusations, and does not moralize. Feedback must be concrete, tied to a specific example where possible. It is given in the first person, with ich, I, and not with man, one.