The NHS Data Model and Dictionary contains classes, attributes, data elements, NHS business definitions and supporting information, relating mainly to data sets which have been approved over time by the Information Standards Board for Health and Social Care, Standardisation Committee for Care Information (SCCI), Data Coordination Board (DCB) and Data Alliance Partnership Board (DAPB).
During development of new data sets, or changes to existing data sets, it may be necessary to ‘retire’ these entities in their entirety, or to retire parts of their associated definitions or National Code lists.
Retirement may also be undertaken when:
- an entire item, such as a data set, no longer has a national requirement to flow (by, for example, the Department of Health or other original owner), or
- where subdivision of National Codes is required for improved national reporting. In the latter case, the original existing National Code would be retired (to maintain its integrity for historical analysis), and new National Codes created
The NHS Data Model and Dictionary is required to indicate where an item used to be a national standard, but that item has been retired. This is to enable historical analysis and research work to continue to be supported.
However, it is critical that ‘old’ definitions and entities are not assumed to be still active by the customers of the NHS Data Model and Dictionary. Items related to the retired item (for example, Data Elements which were once used in the retired data set, and remain active in the NHS Data Model and Dictionary in use in other data sets), should also retain their integrity in the context of the retired item.
The NHS Data Model and Dictionary is required to indicate where an item used to be a national standard, but that item has been retired. This is to enable historical analysis and research work to continue to be supported. However, it is critical that ‘old’ definitions and entities are not assumed to be still active by the customers of the NHS Data Model and Dictionary, and that items related to the retired item (for example, Data Elements which were once used in the retired data set, and remain active in the NHS Data Model and Dictionary in use in other data sets), also retain their integrity in the context of the retired item. For example, if an active Data Element’s definition has changed since it was used in a retired data set, some customers of the NHS Data Model and Dictionary Service may assume that the current live definition was also valid at the time the retired data set was active, where this might well not be the case.
In order to mitigate these risks, the NHS Data Model and Dictionary Service have developed a mechanism to archive previous versions of the NHS Data Model and Dictionary. The definitions of items which have been retired are replaced with a page informing the customer that the item is retired and directing them to the appropriate archived version of the NHS Data Model and Dictionary, if access to the item and the definitions of its components at the time of retirement is required.
