Help and guidance

The NHS Data Model and Dictionary is modelled using the following convention and naming:

• Data Sets are built from a series of Data Elements and, optionally, groups of data elements.
• Data Elements are a specialised use of Attributes for use within the context of the data set. For example they may introduce default codes applicable to a specific data element, perhaps to handle circumstances where data are not available.
• Attributes describe the properties of Classes and provide common data definitions for classes. A class may in turn be a specialised form of another class (a subtype).
• Classes describe aspects of the health and care business with their significant characteristics through their Attributes and their relationships to other Classes.
• NHS Business Definitions describe specific applications of Classes within the context of the health and care system but don't introduce new attributes or relationships.
• Supporting Information is not a part of the NHS Data Model but provides additional context for the reader.
• XML Schema Constraints provide details of restrictions on the data permitted in XML schema for data sets.
• Retired items are not included in the current definitions but are listed in the All Items Index.