The writing of laboratory reports is a common evaluative practice for engineering students, since it allows students to develop empirical thinking skills, and thus, to relate concepts with systematic rational operations in order to describe and explain the phenomenon under study. As it happens with other written genres in this discipline, students present several difficulties in the process of representing the observed experience through writing, which is manifested in the use of linguistic norms, the adequacy to the academic style and the discursive genre. Given the above, the feedback provided by the evaluators becomes a fundamental part for students to correct their shortcomings and improve their level of academic writing. The aim of this article is to characterize the feedback in the measurement laboratory reports of Electrical Engineering students at PUCV. For this purpose, the comments delivered by evaluators to 50 laboratory reports were analyzed based on three feedback typologies, namely those proposed by Contreras and Zuniga (2017), Canabal and Margalef (2017) and Guasch, Espasa, alvarez and Kirschner (2013). For their categorization and analysis, the QSR software Nvivo pro 12 was used. Among the findings, it is observed that evaluators use a wide variety of types of feedback, with corrective feedback being the most frequent. This is used to comment on the successes and errors in the students' writing, focusing on the content, the task or the process of the task. In addition, two new types of feedback emerge from the analysis: praise+projective improvement, corrective+suggestive and corrective+epistemic. Finally, a non-linear decrease over time of the feedback is observed, which implies an improvement in the writing process by the students from such feedback.