The indicators calculated by (SDES) are firstly corrected for calendar effects (trading day adjustment - TDA). The gross monthly data is in fact adjusted according to the specific structure of the month in question in terms of working days (number of working days, public holidays), compared to a mean structure.

The data (TDA) is then adjusted for seasonal variations (seasonal adjustment - SA) by estimating the seasonal component (e.g. month of August generally low).

The selected scope is the new private car registration. The data do not include car registration in overseas departments and overseas territorial authority, car in temporary transit (car sold to non residents), the civil administration of the state and military cars.

The scope, the calendar effect correction technique and seasonal adjustment method used by SDES differ from those used by the French Automobile Manufacturers Association (CCFA). Accordingly, the indicators produced and disseminated by these two bodies differ.

The indicators calculated in this manner are:
- the level of new car registrations, in thousands;
- monthly trend as a percentage;
- quarterly trend as a percentage.