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Accuracy and reliability

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Population and Education, Social Statistics
Jens Bjerre
+45 39 17 36 77

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Childcare before school start

The inventory for 2020 has information from all 98 municipalities. The accuracy is affected by errors in municipal registrations and whether keys for distributing staff in age groups 0-2 and 3-5 years in 0-5 year institutions are correct. Employees and children from private institutions are not included in the statistics, because of an unrealistic high or low ratio of children pr. Employee in such institutions. Moreover uncertainty comes from single registration errors that do not give systematic errors in the calculation.

Overall accuracy

The inventory for 2020 is the first publication of 2021 and contains information from all 98 municipalities.

The statistics are based on register data and cover all children enrolled in public day care institutions and independent daycare facilities with a municipal operating agreement. It is considered unlikely that a large number of children or staff will not be registered in the system, since registration regarding parental payment is used as part of the municipal administration. However, the overall precision can be influenced by staff who do not register institutions, employees or children correct. To compensate for these errors, Statistics Denmark sent an inventory of children and staff for validation in the municipalities.

The municipalities report a key that describes how many staff are working in the age groups 0-2 years and 3-5 years in age-integrated institutions (institutions with children in the age group 0-5 years, where age groups can be 0-2 years and 3-5 year). It might affect the accuracy of cross-municipal comparison if there are significant differences in the value of these keys. Statistics Denmark is aware of the issue and has made comparison of distribution keys across the municipalities.

The inventories do not cover employees with pedagogical tasks and children in private institutions. In the validation of the data from private institutions, comparisons were made to the number of children compared with the number of employees with pedagogical tasks. A similar comparison was made between the number of institutions and employees with educational tasks. During these comparisons, there were private institutions that had, for example, few or no children per adult and other institutions with over 20 children per adults. In other cases, there was a lack of systematic information on employees and staff from some private institutions. It indicates systematic errors in the data that Statistics Denmark has collected on children and employees from private institutions. It indicates that information on employees and children from private institutions contains systematic errors, which is why they are omitted from the inventories. It has not been possible to find the explanation for the systematic errors. A special focus area for the work in 2019 and 2020 is to improve registration and data collection from private institutions

Sampling error

Not relevant for these statistics.

Non-sampling error

The quality of the data is based on correctly registration from institutions and municipalities. Random errors such as incorrectly stated CPR numbers can cause employees and children to be underestimated in the inventories because Statistics Denmark removes duplicates and non-valid CPR numbers in processing of checking data for errors. It is assessed that such errors are random and therefore do not have a systematic effect on the precision of the statistics.

The errors are also improved through the dialogue between the municipalities and Statistics Denmark. Here, errors in the data which do not match municipalities' expectations on the same data will often be identified and corrected. The municipalities indicate how many employees with pedagogical tasks look after children in institutions where there are both children in the age of 0-2 year and 3-5 years (for 0-5 years old institutions). The municipalities do not have a specific value that indicates how many employees look after children in the two age groups. Therefore this number is an assessment by the municipalities.

Correction for maternity leave is made for employees. No correction is made for employees on holiday or sick leave. Temporary employees are counted in the inventory.

In the inventory on the ratio between children and employees report (BOERN3), employees sick leave, holidays etc. appear to equalize, because both children and employees have holidays and sick leave. The inventories are calculated with managers as part of the educational staff in the calculation of the ration between children and employees. It follows the recommendations from the report ”Normeringer i dagtilbud: Model for en årsopgørelse af normeringer i dagtilbud fra 2014” (The ratio of children per adults in daycare – A model to calculate the yearly ratio of children per adults in daycare). On the same background, pedagogical trainees and assistants are included in the inventory, but weighs with a lower factor than ordinary employees.

The ratio between children and employees is an average for a municipality over a whole year, and is therefore not a reflection of a given institution at a given time. The ratio between children and employees does therefore not show the direct time that employees spend with the children - also known as "face-to-face" time. Instead, the statistics reflect the working group’s purpose of calculating a resource allocation for municipalities on day-care. In other words, the inventory is a gross statement of norms in day-care institutions.

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

In the release of the statistic in 2020 all 98 municipalities were published. The publication for 2020 covers BOERN1 (children) BOERN2 (employees) and BOERN3 (the ratio between employees and children). All 98 municipalities are included in the 2020 release, which is a significant improvement compared to 2016, where 78 municipalities were published.

Statistics Denmark has searched the data for errors and validated the number of children and employees with each municipality. The criteria for a municipality to be included in the statistics consist of several steps and is an overall assessment of different criteria. It is a combination of the percentage deviation on relevant factors, the proportion of children who are promoted and the dialogue with the municipality that determines whether data is considered good enough to be published. It should be noted that the purpose of the inventory on ratio between children and employees (BOERN3) is to assess the municipality's resource allocation for the day-care area across municipalities. The quality of the inventory must therefore be assessed on the basis of whether the inventory can be used for cross-municipal comparison. In other words, the inventory of the ration between children and employee is an inventory that looks at the number of children per pedagogical employee in the Danish municipalities and within each parents' board, but it is not a report on the ratio in the individual daycare.

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 figures are published. Numbers are normally only revised if substantial errors are discovered