Accuracy and reliability

Overall accuracy

Since the information originates from the statutory administration, the accuracy is considered to be high.

In assessing whether a service should be included under contacts, there is an element of lack of accuracy.

Physiotherapy is often provided as group training, allowing each physiotherapist to train multiple individuals at once. The training for each individual is recorded as a contact. The same applies when a psychologist conducts group therapy.

The register also includes information about services given to persons without a valid civil registration number – typically foreigners. For these persons, it is not possible to break down on sex and age.

Sampling error

Not relevant for these statistics.

Non-sampling error

There may be measurement errors when assessing whether new services qualify as contacts or not, and if services appear in the registry that are not listed in the fee schedules.

Up to and including 1995, 0-15 year-old children did not have their own national health insurance card, but were registered under the accompanying adult’s civil registration number and given a special mark to indicate that the service was provided to a child. However, this has not been done in all instances. For this reason, the statistics include an unknown number of men and presumably even more women who should have been registered as children. Another issue that contributes to the underestimated number of children is the fact that an adult who has visited the physician with several children or with the same child on multiple occasions during the year, only appears as one person (one child). From 1996 onwards, all persons – except for unnamed new-born babies – have their own national health insurance card with their own civil registration number under which they should be registered. In spite of this, a minor group of children are still reported under the civil registration number of the accompanying adult. It implies a further risk of double counting of these children, as they may first have been registered under the civil registration number of an adult and subsequently under their own civil registration number.

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

Administrative data with full coverage are used. Changes in services included in the agreements from year to year, as well as the fact that Statistics Denmark manually classifies health insurance services as contacts each year, affect the precision—particularly of the number of contacts. The statistics are typically published shortly after, and at the latest half a year following the end of the reference year, making them timely. In general, user needs are met. However, there is demand for statistics on contacts with providers who not receive public subsidies, diagnoses made in the primary care sector, and private expenditures on health services—areas that cannot be covered due to a lack of data.

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

Only final figures are published. As an exception, In connection with the release of the 2024 figures and the new tables in May 2025, a review of services and the delineation of contacts from 2021 to 2024 has been carried out. This has, to a greater or lesser extent, affected the figures in the tables and the number of contacts in the registers.

In September 2022, the basic data (SSSY) was expanded with the variables registration time and treatment date, and the statistical tables for 2021 were reissued. This was due to minor changes in the statistical production: Individuals with invalid CPR numbers, individuals with child markings, and corrections (negative values for services) that cannot be associated with a registration in the respective fiscal year are deleted. The first registered gender and the first registered age are used for individuals appearing in the registry with multiple CPR numbers. Registrations where the variable 'SIKGRUP' (Health Insurance Group) has the value 9 (Deceased) are deleted.