Accuracy and reliability

Overall accuracy

The data come from a single administrative register system storing information on all reported crimes. The statistics are made based on the data recorded at the time the extract is made. There is also produced an annual statistics for this area, which is more complete because it includes reviews that are registered too late to be included in the individual quarters. Comparisons between the quarterly statistics and the annual statistics reveal that the quarterly statistics under-estimate the number of reported criminal offences with approximately 6 percentages.

A general problem in respect of the statistics on reported criminal offences is hidden criminality, which concerns crimes which do not come to the knowledge of the police. It is difficult to give an exact figure for the level of hidden criminality, because it depends among other things on the nature of the crime and the inclination to report crimes.

The Ministry of Justice and others regularly conduct victimization surveys, where the respondents are asked whether an experienced criminal offence was reported to the police or not. From these surveys it appears that e.g. 47 percentage of violence incidents in 2023 were not reported to the police. The victim surveys can be found on the Ministry of Justice's website under the title Udsathed for vold og andre former for kriminalitet.

There is, from quarter to quarter, a shift in the data; part of the registered reported crimes in a given quarter may refer to a previous quarter. In the last 8 quarters 16-20 per cent. of registered reported crimes in one quarter, concerned a previous quarter.

Sampling error

Not relevant to this statistics.

Non-sampling error

For example, victim surveys show that the statistics on reported criminal offences underestimate the actual crime rate, as far from all violations are reported to the police. A reliable total figure for this so-called hidden crime cannot be given, as the tendency to report depends, among other things, on the nature of the violation. The Ministry of Justice and others regularly conduct interview-based victim surveys, where questions are asked whether a crime has been reported to the police. These surveys show, for example, that 47 percent of cases of violence were not reported to the police in 2023. The victim surveys can be found on the Ministry of Justice's website under the title Udsathed for vold og andre former for kriminalitet.

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 statistics are based on a central administrative register and cover all reported offences, except for offences under the Traffic Act. This ensures high coverage and timeliness. However, the quality of the data is affected by when reports are registered and whether the matter is reported at all. Quarterly reports underestimate the level in relation to annual statistics, and the number of unreported offences varies with the nature of the offence. Data is checked by comparison with previous periods, and the police classifications are converted to a uniform structure. The groupings used are continuously adjusted in accordance with applicable legislation, and this may affect comparability over time. The statistics are published quickly and without delay.

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 figures are not revised.