Accuracy and reliability

Overall accuracy

The quality is in general considered to be very good for the income types included in the statistics.

As the income statistics are based on full-population registers, there are no sampling errors or risk of bias.

The income information in the registers of the tax authorities are assumed to be correct. Undeclared income and mistakes in the reporting of incomes to the tax authorities will result in a mismatch between actual and registered income. One-time payments, such as insurance payments and winnings from gambling, are not part of the statistics either.

Sampling error

The administrative registers fully cover the population. Thus there is no statistical uncertainty

Non-sampling error

Undeclared incomes and mistakes in the reporting of incomes to the tax authorities will result in a mismatch between actual and registered income. One-time payments, such as insurance payments and winnings from gambling, are not part of the statistics either.

The statistics include imputed rent for homeowners. It is assigned as a percentage of the public tax evaluation of owned real estate. This income is purely theoretical and is subject to uncertainty.

Data on benefit for heating for pensioners has been imputed for 2020, due to missing data on the payouts.

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

Undeclared income and mistakes in the reporting of income to the tax authorities will result in a mismatch between actual and registered incomes. One-time payments, such as insurance payments and winnings from gambling, are not part of the statistics either. As the income statistics is based on full-population registers, there are no statistical uncertainty and the overall quality of the tax statement is considered to be quite good as the tax statements have to be approved both by the tax authorities and the individual taxpayers.

The income statististics are not revised. This means that any revisions made after the date of the data extraction will not make it into the statistics. Personal tax statements can be revised for up to 5 years following the end of the tax year. Timelines have been improved from December to September by using an earlier data extraction from the administrative tax registers.

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

There is no revision. However a preliminary statistic is published about 6 months earlier (a-income statistics). This statistic only covers wages and transfers. On these parameters the difference to the final register is less than 0.12 percent In total the a-income makes up 85-90 percent of total pre-tax income as it does not include entrepreneurial and property income.