On Apr 8, 2008, at 6:50 PM, Kashyap, Vipul wrote:
Fundamentally, the only interpretation that works is to regard codes as being "meta" to the ontology. I.e. the individuals in the ontology are things in the conceptualisation of the world - cases of diabetes, people, livers, etc. - individual codes represent classes in the ontology. [VK] Agree. Codes represent classes in some ontology or information model.
IMHO, codes don't represent classes in some information model. An information model has classes like Observation, whose instances are clinical statements made by some entity (person or machine). I think information model is "meta" in the sense that its instances are statements (The observation that "John has diabetes") about something that happens in the real world (the person named John has an instance of Diabetes). In BFO term, the observation is an instance of information-content-entity, as opposed to an assertion about the John instance of Person and an instance of Diabetes.
The entire information structure - HL7 or Archetypes - in fact, is at a meta-level. [VK] Agree with this. In particular, the HL7/RIM has a very confusing construction. It could be viewed as a meta-model but then it also has fields to store patient data, For e.g., one may view a class of lab values, say HbA1c as an instance of the RIM Observation class (making it a meta-class), however, the RIM Observation class also has the value field for the value of those labs and is in some sense a multi-layered representation, which is probably why it is so confusing.
I don't understand how a class of HbA1c can be an instance of the RIM Observation class. I don't see how the Observation class having the value field is the issue.
Samson
