The ISEE (Equivalent Economic Situation Indicator) is an Indicator used for the bags DSU (Diritto allo Studio Universitario) and to the graduation of the contribution of a student. To achieve this must be submitted according to the deadlines (usually within the first few months of the year), by using the Online Services. This must be of the current year, then you can only take from the month of January. Pay attention to the times: it requires several days to get this document. You can find the bands contribution here: https://www.polimi.it/studenti-iscritti/tasse-borse-e-agevolazioni-economiche/contribuzione-studentesca/graduazione-del-contributo-onnicomprensivo/