This article reflects on the notions of educated linguistic norm, standard linguistic norm and formal written mode in order to establish a productive dialogue with Portuguese teachers, especially those teaching and assessing their students’ written productions. We questioned some common procedures involved in the grading of written productions, such as focusing on grammar aspects of the texts based on obsolete grammar rules. In order to do so, we discussed the often overlooked and controversial senses associated with terms such as “educated” and “standard”, used interchangeably, for instance, by the graders of Brazil’s National High School Exam between 1998 and 2014 when assessing the written part of the exam. Later on, we performed a qualitative analysis of a school essay that presents a few particular morphosyntactic aspects that are in fact used by “educated” Brazilians in their daily and monitored writing practices. We sought to demonstrate that grammar tradition itself already often validates these aspects in their prescription. This way, possible interdictions in formal written contexts, such as in the National High School Exam, arise from an ideology that preaches unattainable standard linguistic rules, resulting in an obsolete, “pure” and overcorrect linguistic standard.Keywords: standard linguistic norm, grading, written production.