Accuracy and reliability

Overall accuracy

The reliability of the road traffic accident statistics is estimated as solid. Both in the paper system and in the new electronic system the police report the information to Statistics Denmark/the Road Directorate while filling in the police report. That way Statistics Denmark's information on road traffic accidents involving casualties is as close to that of the police information as possible.

The number of road traffic accidents involving casualties who is registered by the police and thereby by Statistics Denmark/the Road Directorate is highly underestimated in proportion to the actual number. In average only 20 per cent of the casualties come to the knowledge of the police.

Sampling error

Not relevant for these statistics.

Non-sampling error

Not relevant for these statistics.

Quality management

Statistics Denmark follows the recommendations on organisation and management of quality given in the Code of Practice for European Statistics (CoP) and the implementation guidelines given in the Quality Assurance Framework of the European Statistical System (QAF). A Working Group on Quality and a central quality assurance function have been established to continuously carry through control of products and processes.

Quality assurance

Statistics Denmark follows the principles in the Code of Practice for European Statistics (CoP) and uses the Quality Assurance Framework of the European Statistical System (QAF) for the implementation of the principles. This involves continuous decentralized and central control of products and processes based on documentation following international standards. The central quality assurance function reports to the Working Group on Quality. Reports include suggestions for improvement that are assessed, decided and subsequently implemented.

Quality assessment

The reliability of the road traffic accident statistics is estimated as solid. Both in the paper system and in the new electronic system the police report the information to Statistics Denmark/the Road Directorate while filling in the police report. That way Statistics Denmark's information on road traffic accidents involving casualties is as close to that of the police information as possible.

The number of road traffic accidents involving casualties who is registered by the police and thereby by Statistics Denmark/the Road Directorate is highly underestimated in proportion to the actual number.

The reason is that the road traffic accident statistics do not include accidents involving casualties, which are not reported to the police. The severity of the accident and the mode of transport are factors, which influence whether the police are involved. Examinations - pooling with the Register of Causes of Death and with registries of casualty award visits and hospital admissions caused by road traffic accidents - have proven that almost all accidents involving deaths are reported. Accidents involving serious personal injury are more frequently reported than accidents involving only slight injuries. Furthermore, accidents involving cars are more frequently reported than accidents involving bicycles and mopeds. In average only 20 per cent of the casualties come to the knowledge of the police.

Data revision - policy

Statistics Denmark revises published figures in accordance with the Revision Policy for Statistics Denmark. The common procedures and principles of the Revision Policy are for some statistics supplemented by a specific revision practice.

Data revision practice

The provisional monthly account differs slightly from the final annual account of accidents, casualties, deaths and injuries. In 2002, the final number of accidents was 0.4 per cent less than the provisional figure. The final figures for the number of injuries and deaths were 0.3 per cent more and 0.9 per cent less, respectively, than the provisional figures.

Since 1 January 2003 only final statistics is published.