In the context of university higher education at undergraduate level, the model of student-institution integration, proposed by Tinto & Cullen and later refined in some of its parts, has often been used to explain the process of dropout/persevere, and even to anticipate such events. This paper approaches the evolution of the Tinto's model since its proposal and reports an analysis of versions of the model found in the literature. The conducted analysis was directed with focus on how to make the model operational, in a way that it could be implemented by universities as an academic computational support system for predicting dropouts. Aiming at its future computational implementation, the analysis approaches the model in relation to its lack of precise definitions of some concepts employed, the loose specification of both, variables and processes involved and questions the extreme importance given to the social integration aspect experienced by students, for explaining dropout.