The analysis of students’ texts requires from the teacher scientific knowledge about language which provides him subsidies for the diagnosis of the writings. Thus, this paper aims to present some reflections on the possibilities of using a diagnostic table, designed with the purpose of guiding the teacher – when assessing the student’s text – in the identification of the mastered and non-mastered aspects in writing. The designing of the table is the result of studies carried out by a study group on Portuguese language, consisting of teachers of the early years and supported by the theories of speech genres (BAKHTIN, 2003) and text genres (BRONCKART, 2003), the concept of text as a teaching unit (GERALDI, 1984) and, more specifically, the discussions on practices of linguistic analysis (GERALDI, 1984 and 1997). In order to test the use of the table, we will take texts of the genre ‘note’ produced by students of the 3rd year of elementary school, considering genre, text and spelling aspects.