Accuracy and reliability

Overall accuracy

The balance sheets are based on a wide range of different data sources which includes both sample surveys and censuses. There are different uncertainties on the different sources, The stock of cereals at farms have some uncertainty because of a small sample. The uncertainty is smaller on the harvest of cereals, both because of a larger sample, a high response rate and it is the largest cereals calculated on area.

Sampling error

There are some uncertainty on the stocks of cereals at farms. The sample represent a relatively small share of the population, why it is very important for the uncertainty that the response rate is high. The response rate was 99 per cent. Regarding sample errors for the statistics on harvest of cereals and international trade of goods, see Harvest of cereals etc and International trade in goods

Non-sampling error

The utilization of cereals is based on differences sources, where the uncertainty is different. The loss in the sample is 1 per cent but the sample only represent a small part of the population. The data on the use of cereals for feeding are subject to some margin of errors, as the use for feeding is calculated as a residual in the balance sheets. All primary statistics to the calculation of the Utilization of cereals has the same target population which indicates no coverage errors in the statistics. There is always a risk for covering more than the population when using more than one source but is thought to be insignificant for the statistics.

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 compiled on the basis of different sources, each contributing with statistical inaccuracies. Especially the coverage of the stocks of cereals at trading companies is good whereas the uncertainty is larger for the data on stocks of cereals at farms because it is a relatively small sample survey. General the quality of the statistics is regarded to be very good.

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 can be some deviations between preliminary and final statistics exist because of deviations between preliminary and final harvest statistics and between provisional and final external trade statistics. The statistics is preliminary in 2,5 years after the end of the reference period.