This paper deals with the study of the practices of teachers in relation with student learning strategies within the classroom. We will focus in particular on how individual oral assessment is carried out. Our aim is to describe, understand and explain the work of nine teachers, five in primary and the four others in secondary education. It was shown that their verbal assessment habits can be characterized by both intra and between individuals as well as by a certain number of stabilities. Through the use of video-taped sequences and statistical processing, we can make sense of these variations and stabilities by studying the correlation between the level of teaching, the level of education and the gender of the student population.