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Important note on aggregation of data |
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2008-02-23 |
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UK trade information is compiled from trade declarations made at 8-digit Commodity Code from the UK Tariff (HS Nomenclature). The nature of Supplementary Units can be different between 8-digit Commodity Codes (e.g. one could be square metres, another could be cubic metres). Quantity should be consistent up to 2-digit level at which point there may also be differences (e.g. one Chapter may be litres, another may be kilograms). Thus when aggregating above 8-digit level the figure created for Supplementary Units may be unreliable and the figure created for Quantity may be unreliable above 2-digit level. Value (£ Sterling) is consistent throughout and can be reliably aggregated. In cases of doubt please refer to the UK Tariff for full definitions or feel free to e-mail us for further advice Index of the Trade Data Dimensions with Basic DescriptionsThe items listed below will help the user to better understand the data being viewed and provides useful background information to place it into context. - -Units
- For each comcode there is a quantity (usually weight but sometimes number for larger items) and statistical value in £ Sterling. Some, but not all, comcodes have a second quantity known as supplementary units which can be number of items if the first quantity is weight, or another weight if required for import duty calculations (full details are set out in the UK tariff which is available from The Stationery Office) . Combinations of selections are possible if desired.
- -Country
- There are 3 levels of information on countries: world, country group and individual country (the lowest level). It is possible to drill down to individual country level for information at this level without reporting on higher level totals if required. Combinations of selections are possible if desired.
- -Comcode
- There are 4 levels of information on goods: total trade, Chapter (2-digit) level, 4-digit level, and 8-digit level (the lowest level of detail). It is possible to drill down to 8-digit comcode level for information at this level without reporting on higher level totals if this is what is required. Combinations of selections are possible if desired.
- -Period.
- There are 3 levels of information: whole year, by first, second, third or fourth quarter and month (the lowest level). It is possible to drill down to month level for information at this level without reporting on higher level totals if this is what is required. Combinations of selections are possible if desired.
- -Revisions
- The figures for EU and non-EU trade in goods are subject to revisions, not only because of late response but also because returns may require subsequent amendment. Revisions may also arise following detection of errors in original returns. For example, where there has been misclassification of goods, or the basis of valuation is incorrect.
- -Suppressed Data (Summary).
- Some sensitive information is suppressed in all HM Revenue and Customs publications. Aggregated, and thus non-attributable, data is included at Chapter (2-digit) level. But the detail of this information will not appear at 4- or 8-digit level. You are advised to run a separate enquiry at 2-digit level, Suppressed Data, and world level in the Chapter(s) in which you are interested so that you can compare the results to establish whether there is any suppressed data at the lower levels. (If you select this enquiry alongside lower level information enquiries, the resulting tables can look very complicated so a separate enquiry is recommended.) Please see the 'Suppressions and Confidentiality' paper from the index.
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