Abstract
It is more and more evident and widespread the separation between the operating evaluation and the theoretic and methodological teaching of the subject. This paper wants to inquiry into the possible reasons that led to this separation between theory and practise through the analysis of the partial expropriation, one of the most frequent estimative cases that the expert has to deal with. This study has the aim of suggesting a methodological framework able to give back the objective criteria, essential for a good estimative advice. This paper tries to identify the separation points between the estimative method and its practical application, starting from the study of what the literature offers on the theoretic subject and going through the analysis of the estimative expertises done in the professional sector.