Abstract

• The process of construction and validation of a tool to observe students at lectures on probability in Primary Education is here presented. Firstly, the specific dimensions, components and levels in the construction process are described; secondly, the results of the content validity process are exposed through expert judgment and subsequent application; and finally, we reflect on the double functionality of the instrument: 1) to improve the knowledge of mathematics teachers when teaching probability; 2) to promote their professional development, with the purpose of designing intervention plans that contribute to the improvement of the teaching of probability.