kilroy | A professional ethics question

I listen to student complaints as part of my job. Because I try to do my job well, I give the students the benefit of the doubt. Most of the time they're coming into my office because they're sincerely distressed or confused about their class-- only rarely do I get someone who's just flat-out trying to bullshit their way into a better grade.

Sometimes, after a while, I get the same complaint from a lot of different students about the same teacher, and I start to give this complaint weight. Usually the systemic complaints mean that the teacher is simply not doing their job in some fundamental way.

The question I have is this: how do I meaningfully get this feedback to the teacher?