The SIRUS statistical register is the main source for the SIDE system. In particular, it provides the statistical variables used to delimit the scope of business demography, such as whether legal units are producers or belong to the market sector.

Although transmitted by SIRUS, a significant proportion of the data used by SIDE comes from the Sirene administrative register (Système Informatique pour le Répertoire des Entreprises et de leurs Établissements). This includes identification data, such as the unique identifier assigned to legal entities and natural persons (the Siren number) and to each of their establishments (the Siret number), as well as data on the administrative status of units in the register, enabling the identification of business births and business deaths.

The economic section is mainly based on data from the Sirene administrative directory, enriched with elements from the Sirus statistical directory (such as producer or
market characteristics, etc.).

In addition to the Sirus statistical directory, the structural component uses various sources
to determine the active nature of units:

- employment data: Base non-salariés, Fichier localisé des rémunérations et de

l'emploi salarié (Flores), Base tous salariés, Epure,
- sales data: Elaboration of activity and sales indicators,
- Liaisons financières, the French directory of groups, with the
presence of ownership links also taken into account to determine
whether legal units are economically active or not,
- Mayotte employment survey.