Accuracy and reliability

Overall accuracy

The overall Material Flow Accounts are based on a range of well-established official statistics. However, the information about the weight of different material types relies in some cases on conversion factors from other units, introducing uncertainty. Additionally, the raw material equivalents are based on a relatively new calculation method involving model calculations and a wide range of assumptions and estimates. Consequently, these figures are associated with greater uncertainty and primarily express orders of magnitude.

Sampling error

Not relevant for these statistics.

Non-sampling error

The compilation of imports and exports is based on information about the weight of imported and exported goods from foreign trade statistics, as well as information about the weight of energy products from energy accounts. There is a certain level of uncertainty associated with the weight information in these source data. Additionally, not all goods are measured by weight in the data sources. Therefore, for some material types, a conversion factor from economic information to material weight is used. This introduces an additional level of uncertainty to the weight information for these goods.

The Material Flow Accounts measured in raw material equivalents are based on a model calculation where the total material consumption for imports and exports of goods is calculated based on estimated raw material equivalents. Since this involves model calculations and estimates, there is a significant level of uncertainty associated with the numbers.

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

No measurements of quality has been done, however the quality of the statistics is seen as best possible, given the resources available for the compilation of accounts. The EW-MFA have the scope and the degree of detail that is on the same level as other countries, such as Netherlands, Sweden and Norway. Accounts are compiled in accordance with recommendations and quality standards provided by UN and Eurostat.

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

Preliminary numbers are compiled and published in March. The final numbers are published in March three years and three months after the reference year.

The publication of the Material Flow Accounts in December 2020 includes a revision of the previously published time series with domestic extraction of the material type 1.3.1. Timber (industrial wood, incl. firewood) for the period 1993 – 2018. The revision incorporates an error correction of the classification of Danish firewood, which must be part of the material type 1.3.1.

The revision includes the domestic extraction of the material types 1.3.1. Timber (industrial wood, incl. firewood), 1.3 Wood and products thereof and 1 Biomass.