Regardless of the level of aggregation envisaged for the dissemination of statistics for particular collections, data should be captured and stored at the most detailed level of the classification possible. This allows the greatest flexibility for the output of statistics, enables more detailed and complex analysis, facilitates comparisons with previous data using different classifications and preserves information so as to provide maximum flexibility for future use of the data.
However, because of collection and confidentiality constraints, it may not be possible to collect, store or output data at the lower levels of the classification in all instances. The use of a standard classification framework will nevertheless enhance data comparability even though it may not always be possible to disseminate data at the most detailed level.
The hierarchical structure of the classification allows users the flexibility to output statistics at the level of the classification which best suits their particular purposes. Data can be presented at major group level, minor group level, the base or country level, or for the alternative standard groups. If necessary, significant countries within a minor group can be presented separately while the remaining countries within the minor group are aggregated. The same principle can be adopted to highlight significant minor groups within a major group.
It should be noted that countries from different minor groups should not be added together to form an aggregation not included in the classification framework (main structure or alternative standard country groupings) as this corrupts the application of the classification criteria and has repercussions on comparability and compatibility with data created by use of the standard. Similarly, minor groups from different major groups should not be added together. In instances where significant countries within a minor group are presented separately while the remaining countries within the minor group are aggregated the group of countries so aggregated should be labelled 'Other', or 'Other Minor Group name'. To invent a label for the 'Other' group is to imply it is a standard grouping of the classification. Similarly, aggregated minor groups within a major group are labelled 'Other'.