CTS2 DSTU Corrections and Enhancements

Corrections:

#	Description	Rationale	Resolution
1	Hierarcy in Concept Domain	There is no hierarchy present in the ConceptDomains in the conceptual model. This can be achieved in two ways. The simplest way is by adding a recursive link in the conceptual diagram. There is another way through which this can be achieved, by adding associations 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.	The way the HL7 CTS2 Conceptual model is now does not allow for the binding of a single code; the binding being done through a ValueSetContextBinding. Use a link between the CodeSystemConceptCode and ValueSetContextBinding.
2	Change ValueSetContextBinding into Binding	The binding is not just done through just the value sets as mentioned - it can be done through a code. Furthermore, there are value sets that are not bound just to the UsageContext only but also to the Concept Domain (like in the MIF file).
3	Change Cardinality in Binding from 1 to 0..1	The creation and definition of a concept domain is done by HL7. Many templates are made by IHE and not by HL7. 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 there is a binding between two entities possible
4	Assure multilingual representation	All the attributes that are indicating a representation of text such as the , "description", "provenanceDetails", "administrativeInfo" should be represented by a format supporting translations.
5	Return Code System Version Details added.	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.
6	List Code System Supplements	Again, this seems to be an oversight.
7	Return Code System Supplement Details	Oversight.
8	List Jurisdictional Domains	It is logical that in an environment with multiple juridictional domains, they should be listed.
9	Return Jurisdictional Domain Details	Oversight.
10	Add an operation which describes the service CTS2 itself.	An operation returning information about the CTS2 service. This is present in CTS, and in the PIM, so it could be an oversight.
11	Add and id of an Association Type.
12	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".
13	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.
14	Addition of a new class EntityVersionCodeSystemVersionMembership	This new association class provides a more robust way of linking Entity Version to Code System versions.
15	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.