The article presents a theoretical study about external evaluations as a propositional element for the diagnostic evaluation of the teacher's work, the teaching network and the educational context. In addition, some conceptions of the expansion of external evaluation are pointed out that contradict the rhetoric that, from a business perspective, the school could generate better results than under the logic of public education. The text is structured in three parts. In the first part, the external evaluation of school learning and its legal aspects are analyzed. Following the analysis, the discourse rooted in static and classificatory precepts was shown, as well as in the exclusionary precepts of education in the single perspective of result. Finally, the analysis and argumentation effort consisted in identifying the evaluation as a diagnostic element of the pedagogical practice in public education, being able to become an alternative for the search for a better quality school performance result.