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Add Support for Subject Populations in CDA R3

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Return to SDTC page; Return to CDA R3 Formal Proposals page.

Submitted by: Austin Kreisler Revision date: <<Revision Date>>
Submitted date: 3/24/2009 Change request ID: <<Change Request ID>>


CDA R2 was not designed to handle documentation of groups and populations as the subject or record target of a CDA document. IGs are still be developed to handle documentation of populations, but this requires using work arounds that are not consistent with how the RIM now calls for documenting groups and populations.


  • The RIM now calls for documenting groups and populations by including the Entity.quantity attribute with the data type constrained to INT. From the RIM definition of Entity.quantity:
    • A physical quantity specifying the amount of the physical thing represented by the Entity object, either as a count of the members of a group, or as some other physical quantity. In order to explicitly identify a group of like entities, a static model design should constrain the PQ data type of this attribute to INT, thus providing a count of the entities in the group.
  • Add the quantity attrtibute to entity classes used to document record target or subject of CDA documents.
  • Other characteristics of populations may also need to be documented such as criteria for inclusion in a population, such as age, gender, height, weight or other physical characteristic. These would need to be handled as observations associated with membership in a group. This was another item that has already come up in a CDA R2 IG.


  • Work arounds are already being used to document populations and groups in CDA R2 in a fashion which is consistent with the RIM. Obviously CDA R3 needs to handle populations and groups the way the RIM describes.


The E_PublicHealthEntity CMETs already allow documentation of populations and groups. In addition it will allow documentation of instances of groups as well as kinds of groups.

Recommended Action Items

The committee agreed with the approach outlined and recommend that CDA R3 support populations in a manner consistent with other RIM models.


Motion: Made by Austin, Kristi seconded to accept proposal to add quantity as int to identify populations on entities associated with RecordTarget / Subject in the header.

Abstain: 1 Against: 0 For 12 – Motion passes.