>From a non-clinical background I would make these statements - not sure if they are correct or particularly relevant but I'll throw it out there and see if anyone agrees.
(1) A message standard is a commitment between two parties to 'understand' a set of data at a defined level. This is why maximal data modelling at a message level doesn't really make sense - noone can write computer systems that 'understand' all the data in a maximal model. Complete semantic understanding of the content of the message is a _requirement_ for health messaging systems (I may not totally understand every field of a message but I at least have to have an agreement between the two parties as to which fields I am allowed to ignore!) (2) An EHR standard is a commitment to faithfully record data meeting a defined level of structure. Maximal data modelling makes sense because the EHR is committing just to the storage of the data, and to allow its retrieval in a standardised way. The EHR doesn't necessarily have to 'understand' the data, merely has to be able to retrieve and present it. Any semantic understanding that the EHR achieves through archetypes etc is a bonus. (1) and (2) are very different use cases - there may be value in sharing common artifacts or bases for the two (ala the template definitions from Ocean seem to me to be a mechanism to allow the definition of (1) but in a way that reliably and easily transforms into something suitable for (2)) Andrew
