The aim of this paper is to investigate the effectiveness of e-learning. We have compared three populations of student who prepare a French diploma called “Diplôme d’Accès aux Etudes Universitaires” which will allow them to follow courses at the university. Three modalities of courses are offered to prepare this diploma: an online or an evening-class or a correspondence courses. The results from this research indicate that drop is a key factor in estimating the internal efficiency. The chances of successful of online courses student are lower more than twice compared to correspondence courses student. Thus, with this mode of instruction for this audience in particular and this diploma, the chances of success are lower. However, if we do not take into account drop, the online education is as effective as correspondence courses or “face-to-face” courses.