The combined use of these sources makes it possible to reconstitute declared income (before redistribution and imputation of undeclared financial income) and disposable income (after redistribution and imputation of undeclared financial income), with a more precise estimate of benefits actually received at fine local levels, down to the commune and sub-commune levels (IRIS, QPV - city policy districts).

The Filosofi vintage for year N is compiled from income received in year N and declared in year N+1, and from council tax as at January 1st of year N+1. It processes tax data for just under 40 million tax households.

The taxes retained to compute the disposable income are: income tax, local residence tax, CSG, CRDS and social levy on income from property. From 2019, the income tax used to calculate disposable income is the tax on the income of the year.

As in the previous RDL system, the household type is constructed on the basis of age differences between individuals, notably in order to reconstitute couples who are neither married nor cohabiting, nor declared as such in the taxe d'habitation file.