Accuracy and reliability
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Food Industries, Business Statistics.Jeppe Strandgaard Herring
+45 24 44 43 06
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The statistic is based on a sample and the results are uncertain. The precision rely on the covering of the sample. Therefore the sample rate is bigger for vessels with high revenue. The aim is each year to include the 100 biggest vessels in the sample, and that approximately 80 per cent of the total value of landings in Danish fishery come from the vessels in the sample. Investments have the most uncertainty, because exchange of a vessel could result in closure of the fishing firm, and set up a new firm to run the new vessel.
Overall accuracy
About half of the units in the population are included in the sample, but because the sampling is biased towards the biggest units, more than approximately 80 per cent of the total revenue in Danish fishery is produced by the units in the sample. Data for the remaining 20 per cent of the production/revenue is known from the register. Therefore it is only necessary to estimate the cost variables for approximately 20 per cent of the total production.
Investment is the most uncertain variable, because replacement of a vessel may lead to closing down of the fishing firm, and the new vessel could then be run by a new fishing firm.
Sampling error
The main variables production and Gross output comes from administrative registers. There is no sampling error.
Non-sampling error
Uncertainty can be connected to failure of the coverage due to that panel selection and not random selection of the sample is used because the report of accounts is voluntary.
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 accounting forms are completed by professional accountants, who themselves have interest in the publication of the statistics, and who furthermore get paid for reporting the data. The harmonized accounting form, the tests and thorough examination of the reported accounts, and finally the comparison with register data all together contribute to secure the data quality.
Production and revenue from sales are important variables in the statistics that are registered for all units in the population. Therefore the coverage of the sampled accounts is known. The quality of the simulated accounts cannot be calculated (see model assumption error), but the good coverage of the reported accounts indicate, that the error on the estimated variables in the simulated units are less significant in the 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
There is not planed revisions for the statistics. Final data are published together with the NYT from Statistics Denmark's press release.