A value domain provides a set of permissible values by which a data element can be implemented. Value domains can be enumerated (e.g. Total centimetres NNN) or non-enumerated (e.g. Sex code N).
The union of a specific value domain with a specific data element concept creates a data element. For example the data element concept Person—body height can be implemented through union with the Total centimetres NNN value domain.
Non-enumerated value domains can be wholly or partially based on a single classification scheme.
Below is a graphical representation of the relationship between value domains and related metadata item types.
Figure 1: Diagrammatic representation of value domain relationships in METeOR metadata structures.