Accuracy and reliability

Overall accuracy

No quantitative assessment of the overall precision of the statistics exists.

Sampling error

Not relevant for these statistics.

Non-sampling error

The main non-sampling error is the measurement error concerning classification at the most detailed CN level, as respondents do not always report sales according to the correct codes. Furthermore, data on quantities are generally less reliable than those on values, as some respondents estimate quantities and others do not answer, implying that estimations must be made in the statistical production process.

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 main non-sampling error is the measurement error concerning classification at the most detailed CN level, as respondents do not always report sales according to the correct codes. Furthermore, data on quantities are generally less reliable than those on values, as some respondents estimate quantities and other do not answer, so that estimations must be made in the statistical production process.

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

With each release of data for a new quarter, data for previous quarters are also released in revised form. Data are always provisional at the first release.

In theory, data for Manufacturers' sales are never final. This means that it is always possible to revise the data if significant errors are found. In practice, data are not revised indefinitely, but are revised in accordance with the following guidelines:

• Late data reports are always incorporated, but normally data are never reported more than one year late
• When Statistics Denmark finds errors in reported data, they are corrected. Errors are not always detected before the first release, especially errors regarding the detailed distribution according to CN codes and the data on quantities. Errors are normally corrected in all quarters of the year when they are found, plus in all quarters of the three previous years.
• Once a year, a revision of industrial classification for reporting units is carried out. Based on reported CN codes and other sources, some units are allocated with a different classification. This is implemented with the first release of the fourth quarter each year, but the three previous quarters are also revised with the altered classification. Normally, between 30 and 70 units change classification.

Data older than the current year plus three previous years are thus only revised in very special cases. The release of 2nd quarter 2014 has been the only recent case of this type, in which turnover for manufacturing of pharmaceuticals was revised for the period 2005Q1-2014Q1, due to changed reporting's that improved the coverage.

Data on manufacturer's sales of goods are submitted to Eurostat annually for the previous reference year. If major revisions have been made since the last data submission, a revised version of previously reported data is also submitted.