CTS2 DSTU Corrections and Enhancements

Corrections:

#	Description	Rationale	Resolution
1	Hierarchy in Concept Domain	The hierarchy is missing in ConceptDomain class. There are two way in which this can be resolved: 1. Adding a recursive link to indicate the parent-child relationships 2. Adding a class called ConceptDomainAssociation between concepts domains. This will allow for finer typing of the relationships between concept domains, not just parent-child relationships.

The following are enancements to the DSTU from a functional point of view. Some of them are present in the PIM but not in the DSTU, so they might be an oversight. Some operations too are also an obvious oversight, so they are not really enhancements.

Enhancements:

#	Description	Rationale	Resolution
1	Binding to a single code.	A link between Code System Node and (ValueSetContext)Binding allowing for the possibility to have the binding of a single code to a Usage Context or a Concept Domain. This is particularly useful in the cases where we have a value set that contains only one code and must have an OID such as in Anatomic Pathology for example.	The sense of the WG is that the association between concept domain is a ‘proper part’, not a recursive ‘is-a’, but also not a typed associative class linkage either. Ana and Nicola will do some paperwork preparation and bring it forward on the next call for a decision.
2	Change the wording "ValueSetContextBinding" into "Binding"	CTS2: ValueSetContextBinding. Core Principles: ContextBinding. However, the functional model supports binding for vale sets and directly codes (enhancement number 1) and between usage context and concept domains in equal measure. A more appropriate name in this case is just “Binding”.	Carmela suggests that the name for the binding should be changed to just ‘contextBinding’, and this seems good.
3	Change Cardinality in Binding from 1 to 0..1	There are many templates generated by IHE. Binding takes places generally between a template and a value set (or a version of a value set). The concept domain is “forgotten”, or implicitly included in the template via the context it describes (in its title, or the subject described in the template, or in the text of the template). This means that in reality we only bind two entities (no Concept Domain). Replace 1 by 0 so that the binding between two entities possible.
4	Addition of a new class EntityVersionCodeSystemVersionMembership	This new association class provides a more robust way of linking Entity Version to Code System versions.
5	Add an id of an Association Type.	An identifying attribute added to the class AssociationType as associationKind is not specific enough.
6	Additions to the Value Set Class to be able to support FHIR functionality	The possibility of a value set restricting another value set. Adding the possibility of a value set version to be authored (provenanceDetails might not be a strong enough representation). Adding an attribute contentDefinition so that the ConceptSet and Filter can be functionally supported.
7	Return Code System Version Details	This is an oversight. The Return Code System Details operation is present; it is a natural conclusion Return Code System Version Details was omitted. This is present in the PIM.
8	List Code System Supplements	Again, this seems to be an oversight.
9	Return Code System Supplement Details	Oversight.
10	List Jurisdictional Domains	It is logical that in an environment with multiple juridictional domains, they should be listed.
11	Return Jurisdictional Domain Details	Oversight.
12	Return Service Details	An operation returning information about the CTS2 service. This is present in CTS, and in the PIM, so it could be an oversight.
13	Conformance Criteria	The SFM is totally silent of what must be provided by an implementation allowing for declaring it conformant. To the minimum extend, a single function listing all codesystems is enough. To the other extend all functions must be provided. The real necessity is something in the middle: The specific set of functions must be marked. Therefore, a classification and/or prioritization according the functions must be provided. A solution can be the declaration of a basic set of functions and appropriate options. E.g. the handling of value sets may be necessary for certain environments, but not really for all use cases. Therefore, all functions dealing with value sets can be assigned to "option 1".	CTS2N will contain a section dealing with profiles. Furthermore, 5 functions have been identified which must be provided by a compliant service.
14	Licensing Information	For a national use, the server must keep track of who is allowed to see which codesystem and the associated codes. E.g., only persons/institutions having purchased Snomed CT will get a result including Snomed CT.	This feature must be realized with a security architecture acting as a firewall. The policies will describe who has access to what.