The following paper outlines the major findings of a state-of-the-art review of non-academic factors that influence teacher evaluations, and proposes an interview technique to identify freely the concepts students use to evaluate their teachers. Through interview on classification without cards that contain the names of the teachers being assessed, the study shows the psycho-social factors or conceptualizations students employ when evaluating their teachers. In the end, doubts are expressed about the objectivity and validity of teacher evaluations based on structured questionnaires.