Accuracy and reliability

Overall accuracy

The response rate for the public library statistics is 100 per cent.

Uncertainty, due to misreported numbers and misunderstandings, is minimal. This is due to repeated checks of the public libraries' reported figures and ongoing contact with those reporting. Any missing values are not imputed. For research libraries in year 2022, the total response rate for research libraries with special obligations and other research libraries was 100 per cent. In previous years, the response rate has been lower, particularly at the other research libraries. The other research libraries are generally smaller and statistics for them are only published in a table, so the smaller response rate for them does not affect the overall precision. Totals are underestimated if some research libraries do not report to the statistics.

Sampling error

Not relevant.

Non-sampling error

Statistics Denmark receives data on all public libraries in Denmark. Special local conditions such as conversions etc. may result in individual municipalities not reporting data for all variables every year. Central information about lending, stock, opening hours and certain financial information is always reported. Figures derived from the questionnaire about activities at the library and visitor numbers are considered to be slightly more uncertain due to different calculation methods. Incorrectly reported figures and misunderstandings have been sought to be minimised, i.a. in the case of repeated withdrawals in the event of non-reporting, as well as in the case of a thorough check of the reported figures.

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 overall reliability is high, as the public library statistics are based on reports from all library municipalities in Denmark. Local conditions may mean that individual municipalities do not report all variables every year. Central information about lending, stock, opening hours and certain financial information is always reported. Some other research libraries fail to report to the research library statistics. The missing values have never been imputed or enumerated. Therefore, the data is underestimated compared to the actual level. All research libraries with special obligations have reported to the statistics. The statistics are created based on the DS/ISO 2789 standard, which is the international standard for compiling library statistics.

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

Only final numbers are published.