The 'Effective oral communication' is one of the most demanded student outcomes in the workplace, since being a good communicator is essential in any field. Inefficient communication can lead to misinterpretations and erroneous conclusions. Therefore, it is a very important student outcome both in the university and in the workplace. The student or graduate must know how to communicate effectively, both orally and in writing, appropriately using the necessary resources and adapting to the characteristics of the situation and the audience. However, despite its importance, the disparity in the mastery level of the oral communication student outcome by students makes it difficult to work this ability in the classroom through collective activities. For this reason, to properly develop this student outcome in a subject, it is important to have an idea of the main weaknesses that students have in terms of effective oral communication, to be able to establish and carry out actions and training activities that can improve that transversal student outcome. This article presents the analysis of the main weaknesses that students of a university subject have. This analysis is made based on a self-assessment survey, a self-diagnosis, which allows the student to detect their weaknesses and strengths in the domain of effective oral communication, and at the same time, gives information to the teacher about the main deficiencies of their students, so the teacher can devise and launch training activities appropriate to the level of their students