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Relationship groups

Role groups are now called Relationship groups

5.3.1 General guidelines Overview

  • Relationship group combines an attribute-value pair with one or more other attribute-value pairs.
  • Multiple attributes and their values can be grouped together into "Relationship groups" to add clarity to concept definitions. 
  • Multiple "Relationship groups" may be created to fully define a concept
  • Each attribute type that is included in a "Relationship group" may only be present once (i.e. two ASSOCIATED MORPHOLOGY attributes cannot be in the same "Relationship group")
  • Relationship groups originated to add clarity to:
    • | Clinical finding | concepts which require multiple | ASSOCIATED MORPHOLOGY | attributes and multiple | FINDING SITE | attributes; and
    • | Procedure | concepts which require multiple | METHOD | attributes and multiple | PROCEDURE SITE | attributes.
  • Relationship groups are not limited to | Clinical finding | and | Procedure | concepts.
  • As with all authoring activities undertaken by an author, grouping of the attribute-value pairs is performed in the stated view. Ungrouped attributes

An attribute-value pair that does not sit within a relationship group is considered to be in a group on its own. When attribute-value pairs are not grouped their meanings are interpreted separately.



In our example above there is an | Associated morphology | of | Hemorrhage | and there is a |Finding site| of |Uterine structure| but no explicit interpretation that site of the hemorrhage is the uterine structure can be made. The impact of relationship grouping on inheritance

Relationship groups refine inheritance. That means a grouped set of attributes is more specific than the same attributes that are not grouped. This is important to remember when considering subsumption.  The following example using the concept  | Excision of lesion of aorta | and one of it supertype concepts | Excision of aorta |demonstrates the impact of not grouping consistently. 

The supertype concept | Excision of aorta (procedure) | (attribute-value pairs are grouped) 


The meaning of the supertype concept | Excision of aorta | (where the relationships are grouped) has been interpreted as a procedure where an excision was being performed on the aortic structure because the | METHOD | and | PROCEDURE SITE - DIRECT | have been stated (via the grouping) as related together.  

The subtype concept: | Excision of lesion of aorta (procedure) | (without attribute-value pair grouping) 

Note the more general supertype concepts | Excision (procedure) | and | Procedure on aorta (procedure) | which are shown as the proximal supertype concepts.


| Excision of lesion of aorta (procedure) | is a logical subtype of | Excision of aorta (procedure) |. However, while the attributes on the concept | Excision of aorta (procedure) | have been grouped, the attributes on the concept | Excision of lesion of aorta (procedure) | have not been grouped, Thus, the classifier views these definitions as non-related and | Excision of lesion of aorta (procedure) | has not been inferred as a subtype of | Excision of aorta (procedure) |. This is because the association among the relationships in the subtype concept were not explicitly stated and from a machine processing perspective each attribute-value pair is evaluated as a group on its own. For example, there is an excision but nothing else about the excision is known. This leads to the concept | Excision of lesion of aorta (procedure) | being interpreted as broader in meaning. 

By grouping the attribute-value pairs, an author is explicitly stating that the excision is of a lesion found in the aortic structure. This grouping action provides the information that then enables | Excision of lesion of aorta (procedure) | to be inferred as a subtype of | Excision of aorta (procedure) | when the classifier is run.  


The subtype concept: | Excision of lesion of aorta (procedure) | (with attribute-value pair grouping) Identical attributes should be placed in separate relationship groups

Each relationship group shall only contain one instance of an attribute. For example, one relationship group should not include two | FINDING SITE | attributes. This is because two identical attributes within a relationship group are not equivalent to a single attribute with a single target value that captures the combined meaning of the target values. 



In this example | Fracture of radius AND ulna | two | FINDING SITE | attributes are required to support expression of the location of the fractures. Each attribute and its respective target value is placed in a relationship group, together with the | ASSOCIATED MORPHOLOGY | attribute with a target value of | Fracture |.  


5.3.2 Procedure hierarchy

In the Procedure hierarchy, a relationship group is usually a way of combining attributes that pertain to a particular | METHOD |. The majority of relationship groups for procedures group attributes with the | METHOD | to which they apply.

In the example below, the Relationship groups clarify that there is exploration of the bile duct, and excision of the gall bladder. Without Relationship groups, the proper associations among the four attributes would be unclear, i.e. whether the excision was of the bile duct or of the gall bladder.


When there is no | METHOD | stated, the | PROCEDURE SITE | (or relevant subtype | PROCEDURE SITE - DIRECT |, | PROCEDURE SITE -INDIRECT |) is always grouped with the | PROCEDURE MORPHOLOGY |(or relevant subtype | INDIRECT MORPHOLOGY |, | DIRECT MORPHOLOGY |) for that site.

5.3.3 Clinical Finding hierarchy

In the | Clinical finding | hierarchy:

  • The | FINDING SITE |and | ASSOCIATED MORPHOLOGY | attributes are always grouped where both are present (and they are related). 
    • As noted above, in cases where there is more than one | FINDING SITE | or | ASSOCIATED MORPHOLOGY | then more than one relationship group will be required. 
    • Where the | OCCURRENCE | attribute and/or the | CAUSATIVE AGENT | are also stated (and are related to the | FINDING SITE | and | ASSOCIATED MORPHOLOGY |) they should included within the relationship group. 
      • If the | CAUSATIVE AGENT | is an Organism then the | PATHOLOGICAL PROCESS | attribute is also used in that relationship group with the permitted target value of | Infectious process | or | Parasitic process |. 

  • The | INTERPRETS | and | HAS INTERPRETATION | attributes are grouped together where both are present and they are related.
  • The | FINDING METHOD | and | FINDING INFORMER | attributes are grouped together where both are present and they are related.
  • The following attributes are not currently grouped by an author during modelling:
    • | DUE_TO |
    • | AFTER |

5.3.4 Situation with Explicit Context hierarchy

For finding with explicit context concepts the following four attributes are grouped:


For procedures with explicit context the following four attributes are grouped:


5.3.5 Observable Entity hierarchy

Relationship grouping is not permitted when modelling concepts in the | Observable entity | hierarchy.