Accuracy and reliability

Overall accuracy

Rents for residential properties are generally adjusted at the turn of the year or when new lease agreements are signed, resulting in relatively stable rent trends within a quarter. For other property categories, there is greater uncertainty, as rents are more subject to ongoing negotiation. Despite this, the overall accuracy is considered satisfactory.

Sampling error

It is not possible to calculate the sampling error for the commercial real estate rent index, as the sample used is not based on simple random selection. For the residential sector, the sampling uncertainty is considered to be limited due to a sample size of approximately 84,000 observations. For the other property categories, the samples are significantly smaller, so the uncertainty is expected to be correspondingly greater.

To assess the representativeness of the sample, its composition is compared once a year with that of the population. The assessment includes, among other things, geographic distribution, use, and rental conditions.

Non-sampling error

The sample underlying the commercial real estate rent index is continuously validated against information in the Building and Housing Register (BBR). To the extent that the BBR records contain errors, this may result in coverage errors, as the defined population will differ from the target population.

For the three property categories other than residential properties, it is not possible to determine whether individual rental units are occupied. The population for these categories therefore cannot be defined with the same degree of certainty as for residential properties, which makes it difficult to assess the coverage rate. Consequently, there is uncertainty involved in assessing the extent of any coverage errors for these categories.

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

There are no uncertainty related to the calculation, but there are some uncertainty overall due to the categories retail, offices and industry.

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 numbers are published.