CEN/ISO EN13606 Archetype Model
An archetype is a structured and constrained combination of entities of a Reference Model that represents a particular clinical concept, such as a blood pressure measurement or a laboratory analysis result. This structure should be defined by a health domain expert. An archetype can be also defined by further constraining other archetype, called parent archetype, in order to obtain a more adequate or fine grained representation of the clinical concept.
Archetypes are composed of three main sections: header, definition and ontology.
The header section basically contains metadata about the archetype, such as an identifier or authoring information.
In the definition section is where the clinical concept which the archetype represents is described in terms of Reference Model entities. This description is built by constraining the entities in different ways:
- Constraints on the range of attributes of primitive types.
- Constraints on the existence of attributes, i.e. whether a value is mandatory for the attribute in run time data.
- Constraints on the cardinality of attributes, i.e. whether the attribute is multi-valuate or not.
- Constraints on the occurrences of objects indicating how may times in runtime data an instance of a given class conforming to a particular constraint can occur.
- Constraints on complex objects. They can be stated by constraining their attributes or by reusing previously defined archetypes or archetype fragments.
Finally, the ontology section is where the entities defined in the definition section are described and bound to terminologies.
Archetype specialization is the mechanism that allows re-using an archetype definition. This is achieved by providing further constraint on information already expressed by other archetype. There exists an underlying specialization hierarchy behind every archetype whose root is a Reference Model entity. Below it hangs up a parent-children succession of archetypes. The deeper the level of the hierarchy is, the more constrained or specialized the archetype is. Data created as an instance of a specialized archetype is also an instance of more general or parent archetypes and at the same time is compatible with the root Reference Model entity that we are archetyping.