Accuracy and reliability

Overall accuracy

There is likely to be a minor degree of under-reporting, but there are no sources of systematic uncertainty.

Sampling error

Not relevant for these statistics.

Non-sampling error

The statistics on drug abuse include municipality-level data for municipalities that have approved their submissions, as well as national totals that incorporate imputed values for two municipalities for the years 2018, 2019, and 2020. Consequently, the statistics provide complete national coverage for 2018–2025, whereas no national totals are published for earlier years.

Previously, it was not possible to register opioid substitution treatment provided by a general practitioner in the SMDB. This is now possible by creating a service affiliation under “Substitution treatment delegated to another physician.” In the past, many treatment providers registered their own physician as the treating doctor (authorisation code) when treatment was provided under Section 142 of the Danish Health Act, even though the citizen was in fact being treated by a different physician.

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 of the statistics is increasing every year, as work is continuously being done to find new ways to ensure the quality of data and to communicate better and more effectively with municipalities.

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

When a new statistical year is established, previous years are revised back to 2015 in the StatBank, while Micro-data are updated as far back as available data exist. Respondents can make corrections to already reported data or additions of new information daily. These changes will be included in the next publication. Each publication will make an estimate of the size of the revisions on the main figures distributed by municipalities. Relatively few revisions are expected for years that are more than a couple years back in time.