Accuracy and reliability

Overall accuracy

For the reference year 2023 there are 33 enterprises in the statistics and a useful response rate of 100 pct., covering 100 pct. of the total turnover of the population. The lapse are due to wrong industry code and closure of the enterprises and non-responded questionnaires. The usable data from the enterprises grossed up to the total level (the target population) of the 6-digit industries within the sector for Technical testing and analysis by using preliminary turnover from the Accounts Statistics for Non-Agricultural Private Sector.

Sampling error

The sampling error is equal to zero, as it is a total count.

Non-sampling error

The total uncertainty consists of sampling uncertainty and other systematic uncertainty. In other uncertainties include inter alia measurement error and non response error/lapse.

Coverage error

The population is defined by the industry, the enterprises registered in the Business Register by themselves. Errors of classification of the industries will be expected. This means that there may be enterprises in the population that really should not be classified as an enterprise in the sector Technical testing and analysis.

In the context of fault tracing and quality assurance of the statistics, number of these errors continuously are found and corrected. Companies that incorrectly classified as Technical testing and analysis cause over-coverage. These coverage error is detected primarily for companies in the sample, but also in some cases for non-sampled companies.

Under- coverage in the form of companies that are classified entirely outside Technical testing and analysis, even though they should properly be classified as Technical testing and analysis, are difficult to detect, but can be found also.

The total number of enterprises in the population is estimated at approx. 67, and among these the sample is selected. The sample for the reference year 2019 was 67 companies and is thus 100 per cent. of the total number of the population. Because of the stratified selection, where large companies are more likely to selection than the smaller, the sample consists 100 per cent. of the total turnover of the population.

Measurement error

Uncertainty due to lapse, incorrectly reported numbers and misunderstandings has sought to minimize by repeated reminders by non-reporting, as well as by substantial verification of the reported figures.

Generally the services in the questionnaire are based on Statistical Classification of Products by Activity CPA 2008, with an adjustment to Danish conditions. It can be an uncertainty in the distribution of turnover and export by services when the services CPA 2008 are not quite commensurate with the classification of products of the firms.

Non response error

There are 60 enterprises in the sample. The usable questionnaires are from 57 enterprises, i.e. there is a lapse of 5 per cent.

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 quality is estimated to be high as the statistics is based on a total count with a high response rate. Furthermore because because the statistics uses the turnover from the Accounts Statistics for Non-Agricultural Private Sector. The figures are preliminary and will not revised in the national publishing. For delivery to EU the figures are calculated (revised) based on the turnover in the final version of the Accounts Statistics for Non-Agricultural Private Sector.

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 published data will not be revised, since the statistics is published once every second year.