The sources to the car register and its publications are the Digital Motor Register, DMR, and other population and business registers in Statistics Denmark.
The central tables in DMR are processed to a row of files with new registrations, re-registrations, user shifts, owner shifts and stock figures. Depending on purpose data from the above mentioned registers can be added.
The series with new registrations, supply and leasing as well as used car sales of passenger cars are seasonally adjusted. The quality of the adjustment is high and there clear seasonal patterns.
Generally: The Central Register of Motor Vehicles up to 2007 inclusive, from 2008 from SKAT (the overall tax authority)). From 2012 the Digital Motor Register, DMR. Statistics Denmark's registers.
Data concerning the vehicles: The main source of data in the register is DMR, from which data concerning both new and existing vehicles are supplied monthly. Elderly (former registered) vehicles are in the register as well.
The registration of data has been based on forms submitted to the offices of the Central Register of Motor Vehicles / tax centers, typically when the owner or the retail firm wants to perform a transaction (for example a new registration, a change in ownership or a technical alteration). From January 1, 2008 SKAT took over the police assignments regarding the register. The assignments are registration of vehicles and collecting duties. Approximately 60 centres for motor vehicles was shut down. See also Homepage of the tax authorities regarding Motor vehicles..
In June 2012 DMR launched an on-line system to registrations to be used by dealers and others the car market.
The source of most of the technical data of the vehicles is the (standard) type approval, of which there are two main forms; one that is uniform for the EU (and for all similar vehicles) and one that is individual for a smaller group of vehicles or a single vehicle.
MOT-data on all vehicles that have passed a MOT-test are supplied monthly from Trafikstyrelsen (Danish Transport Authority). These data can be joined to the vehicles in the car-register, but they are not incorporated in the register.
DMR is delivered with a system-to-system solution while there are direct access to the population statistical registers. Extract from the business register is delivered as a SAS-file.
Data regarding vehicle owners: The background data concerning vehicle owners are delivered from a range of registers in Statistics Denmark.
There are no routines with respect to quality and errors in the register as the Digital Motor Register, DMR - the main data source - is well equipped with controls and constraints.
A range of cross table controls are established in the production systems of the different publications to prevent discrepancy between new and elderly versions of the same figures and to prevent simple errors across published figures.
The other mentioned registers are validated by the producers in Statistics Denmark.
The monthly deliveries from the Digital Motor Register, DMR consist of approx. 400 data base tables. The key tables are processed to data files with new registrations, re-registrations, owner shifts, user shifts and stocks respectively.
There are no other operations such as imputations or corrections performed on the data.
Seasonal adjustment are performed for the series:
The quality indicators shows clear seasonal patterns and the series are therefore well qualified for correction.