CSCR-064 remove x domain and start vocabulary domain

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Submitted by: William Goossen on behalf of Patient Care	Revision date: May 12 - 2006
Submitted date: May 12 - 2006	Change request ID: CSCR-064

Issue

Move from a x-domain approach to a vocabulary domain that resides with the clinical statement pattern and narratives in the appropriate ballot section.

Rationale:

Background: The x-domain is really a single value set rather than a vocabulary domain.

For a general pattern, like clinical statement, which is used to support many use cases, there is often a specific subset of codes that is appropriate for a specific use case in a message, a collection of messages, or in documents.

With the X-domain specified in the model instead of a vocabulary domain, implementation guide writers must implement a "non-standard" mechanism like a table or list in the implementation guide text rather than using a published value set in order to apply constraints.

The most flexible model for allowing implementation guide developers is for models to specify a vocabulary domain and then allow implementation guides to specify value sets for the vocabulary domain in order to constrain the model for specific needs. This avoids having implementation guide writers use other, non-standard, highly-variable mechanisms for constraining an x-domain.

Recommendation

Start to do this.

Rationale

Due to difficulties with harmonization work for every change request, it is better to have an easier way forward

Recommended Action Items

Set up project team to follow up

16 June 2006 Waiting for feedback to verify that the approach proposed is indeed being pursued to ensure it's easier to maintain.

• Follow Up :

Information on possible steps to follow from Dan Russler 23-Jun-2006 :

1. Examine the current vocabulary domains for the moodCode (in the RIM Vocab Content documentation) to see if any of the descriptions define the scope of the value sets desired 2. If no existing vocabulary domains exist that meet the intent of the Pattern Committee, the first step is to propose a new vocabulary domain to M&M. 3. The next step is to propose a value set to M&M that includes the codes desired by the committee, which ends up being referenced in the Pattern documentation. 4. This then allows implementation guide writers the opportunity to either propose a second narrower value set to M&M or to propose an extended value set to M&M and reference those value sets in the implementation guide documentation.

Here is one example vocabulary domain and value set (note that there are some vocabulary sub-domains in the hierarchy): Information from Russ Hamm 23-Jun-2006

An HL7 Vocabulary Domain is a named category of like concepts (semantic type) that will be bound to one or more coded elements.

Vocabulary Domain

Vocabulary domains exist because we want to constrain the intent of the coded element while deferring the association of the element to a specific coded terminology until later in the message development process. Thus, vocabulary domains are independent of any specific vocabulary or code system.

Domains are universal in nature (independent of any realm). A domain name should never contain any reference to a specific realm. Vocabulary domains are proposed as part of the HL7 standards development process and are approved by the RIM harmonization process. Any conflicts in proposed domains are resolved by the RIM harmonization process.

A vocabulary domain is documented by specifying a name, a narrative description, and three or more examples of concepts that are members of the category.

X-Domain (deprecated)

Explanation for deprecation: "X-Domain" is a misnomer. A more proper name would be "X-value sets", since they are really HL7 defined value sets or sub value sets. X-domains came into existence to address a muddling between the code system hierarchy and value sets. Earlier versions of the vocabulary maintenance tools didn't distinguish between a value set that referenced concepts X, Y and Z and a concept code with subtypes X, Y and Z. The prefix "X-" was added to value sets that were intended to represent simple collections, not conceptual hierarchies. A rule was established that new concept codes couldn't be introduced within an "X-" domain. They first had to be entered elsewhere in the coding scheme hierarchy and then added separately to the "X-" domain. As time permits, all X-domains will be replaced by value sets.