Using diagnostic testing to build effective teaching strategies in mathematics

The purpose of this research is to examine the use of diagnostic testing as a tool to build effective teaching strategies in mathematics, especially at the beginning of the school year. The study has a quantitative approach, where data are collected through a diagnostic test developed on basic mathematical concepts, which are considered the foundation for progress in more complex topics. The sample consists of 70 Primary and Secondary Lower High School students, while statistical analyses are used to identify existing knowledge, frequent errors, and misconceptions. The results show that the diagnostic test not only helps in categorizing the level of students' preparation but also provides valuable information for teachers in building personalized teaching strategies. Through this process, teaching becomes more oriented towards the real needs of students, significantly improving their performance in mathematics. This study highlights the importance of the diagnostic test as a necessary component of formative assessment and as a basis for developing effective pedagogical methods. Overall, the study confirms that diagnostic testing serves not only as an assessment tool but as a formative approach guiding instruction toward students’ real needs. For teacher educators and curriculum developers, it highlights the importance of integrating diagnostic assessment into training and curriculum design to promote data-informed, reflective teaching practices.