Validez y confiabilidad de tareas para valorar el conocimiento conceptual del docente sobre porcentaje

This article presents quantitative research, focused on the construction of tasks with open questions that allow the teacher's specialized knowledge on percentages to be demonstrated, with validity and reliability tests, using the Mathematics Teacher's Specialized Knowledge Model. Six tasks were proposed with questions oriented to the topic of percentages, then they were subjected to a validity test with the support of five experts, and a reliability analysis with five teachers, all with experience in teaching mathematics. The tasks were proposed to obtain evidence of the Knowledge of Topics (KoT) subdomain of this model. The results of the tests applied reflect a high validity and reliability, indicating that the tasks are useful to identify the specialized knowledge of the mathematics teacher on the topic of percentages, that is, related to percentage operations, conversion to decimal and fractional quantities, and their representation records. It is concluded that the tasks allow obtaining evidence of knowledge of the KoT subdomain. Each question encourages broad reasoning and evidence of the topic, mainly arithmetic records. Tasks can contribute to the development of training proposals or teacher assessment on the topic of percentage.