Is it a GDPR breach for a teacher to call out the attendance % for each pupil in the classroom? I think it probably is as it's personal data to each student isn't it.
Even if it's not a GDPR breach I don't think it is very professional behaviour. For context this is a classroom where the students mostly have additional needs and difficulties.
The aim is to scare them into increasing their attendance but the result will actually be the opposite of that as for these children it simply isn't that straightforward. Something this particular teacher doesn't seem to quite understand.
I'm just trying to get a balanced and neutral perspective on this.