This paper analyses the influence of external factors that affect the decision-making process in the selection of telecommunications engineering studies. Particularly, we have studied the influence of factors related to the generation of expectations about the studies. A survey was conducted on a sample of 701 male and female telecommunications engineering students. The results show the existence of a direct relationship between the choice of telecommunications studies in non-vocationally oriented students and their expectations of finding a job more easily, getting higher salaries and more prestige. On the other hand, non-vocationally oriented students show similar academic performance to that of vocationally oriented students. (Contains 6 tables and 2 figures.)