The self-employed database is based on the social declarations of self-employed persons, coming from two main suppliers:
- the Central Agency of Social Security Organisations (Acoss), pilot of the Urssaf network. This covers personal social security contributions for family allowances and the CSG-CRDS based on the remuneration of all self-employed, apart from the agricultural sector;
- the Caisse centrale de la mutualité sociale agricole (CCMSA), which covers social contributions in the agricultural sector.

These data are completed each year with variables from:
- on the one hand, annual social data declarations (DADS) completed by all private companies employing employees. These data are complemented by data from the Public Service Employee Information System (Siasp). The database thus gathers information on the salaried positions held by self-employed who had also a salaried job during the year (multi-activity);
- on the other hand, the "Business Register Identification System (Sirene)" directory (annual reference frame for active establishments as well as a complete directory), then the Registration System to the Statistical Unit Register (Sirus- generic reference frame). This operation makes it possible in particular to validate the SIREN/SIRET identifiers, to determine the real activity of the owner-operators of corporations (SA & SAS excluded) and to enrich the data with characteristics of the companies.

The self-employed annual database contains all individuals who are affiliated with a social protection (or welfare) scheme for self-employed workers and who had at least one day of activity in the year.

The earned income of self-employed persons is calculated on the basis of their taxable professional income, where certain tax breaks and voluntary social contributions are reincluded. In practice, it corresponds to the basis used to calculate personal contributions to family allowances.