Christopher Feahr wrote: >Thank you... this is becoming clearer from the clinical/business-process >perspective. I still have this lingering concern about the inherent >freedom and flexibility afforded by archetypes being somewhat in >conflict with the need for interoperability. Let me see if I understand >by reflecting a specific example of a physician ordering a pair of Rx >spectacles from a lab: > >The "ontology" (which seems roughly synonymous with "data dictionary" >and "standard terminology" a la SNOMED) would be a listing of all the > you need to put a flak jacket on now, due to the missiles the ontologists will be launching in your direction anytime now....;-)
Ontologies are about representation of knowledge, and in their most general form, they _may_ have definition of he atoms, but what they are really made of is semantic links - that is, any atom is really defined by its relation to everything else - just like natural language if you think about it. >"atomic" terms unique to specification of an Rx lens, along with >industry-standard, unique definitions: > the following kind of definitions appear in what most people will call terminologies. There are various typlogies of the terms "ontology", "terminology", "vocabulary", "nomenclature", "lexicon" and so on - one was done by CEN, the Euopean standards organisation, another appears in the Slee, Slee, Shmidt book - The Endangered Medical Record. >SpherePower: "The diopteric power of the blah, blah, blah..." >MinusCylinderPower: "The algebraic difference blah, blah, blah..." >CylinderAxis: "The angle represented by the blah, blah, blah..." >etc., fully specifying the data types, ranges of acceptable values, >units of measurement, and somehow stipulating that only "quarter" and >"eighth" diopter values are used. E.g., "-3.25" and "-3.37" are >acceptable, but "-3.90" is not an acceptable value for the unit, >"diopters". Cylinder axis is express in whole degrees with legal values >from "1" to "179", etc.. > >Then we could define an Archetype called >"BasicLensFormula-MinusCylinderNotation", which is a combination of >SpherePower, MinusCylinderPower, and CylinderAxis, more or less "strung >together". The Order specification message to the lab would require, >amongst other things, the "BasicLensFormula-MinusCylinderNotation" for >the right lens and the "BasicLensFormula-MinusCylinderNotation" for the >left. Is this understanding correct so far? > this probably isn't too far off - I have don't understand the terms you mention sufficiently to do an analysis, but if you consider the information structures of opthalmic & optometry investigations, symptoms & signs, diagnoses, orders, results, and so on, these are where archetypes can help. >If I am using these terms and concepts correctly, then it seems to me >that the most critical objects for doctors and other users to agree on >INITIALLY and memorialize as a "standard"... across the region that >wishes to experience "interoperability"... would be the basic >ontology... correct?? > well - basic terminology would be a good start - at least an agreement of the meaning of basic terms. But (and this is a big one), in our experience with archetypes, we have discovered that many terms which one would have thought have only one standard meaning, in fact have a myriad of meanings, depending on context. This is why some meanings have to be defined locally inside archetypes. Building archetypes with internal definitions is in fact building a part of an ontology; other parts would have to be built with ontology building tools (e.g. Galen is a well known example in the clinical arena; more recently see OWL - see W3C). The more sophisticated an ontological structure you build, the less you can rely on standard dictionary definitions for any given word, because there are multiple definitions available by traversing the ontology paths in different ways through the atom in question. >If the ontology is the listing of "atoms", then Archetypes would appear >to be the "molecules"... and also something that would be helpful to >attempt to standardize across the "interoperability region/domain". But >due to the inherent "anything goes" aspect of defining Archetypes, and >the flexibility in system design that accompanies it, we might have a >harder time getting users to agree on standard Archetypes. If 80% of >the most common "molecular" concepts, however, could be agreed to at the >SDO level, then that would seem to be in everyone's interest. > it would - but as I say above, real ontologies are more like a sponge, or vast octopus-like network of links and concepts - not jsut atoms. >I will assume that I'm still "on the right track" and take my question >to one more level. Would it make sense, then, for the SDO to continue >accepting Archetype definitions that are useful to some in the domain... >even though they might be extensions or conglomerations of other >Archetypes? ... and for the SDO to maintain all of them together in its >library of "standard archetypes for the vision industry"? If Standard >Archetype X was made from unique, atomic concepts A, B, C, and D... and >a user only required A, B, and C... would he still use an Archetype X in >his message schema, simply ignoring the value of D? Or would he >register the combination of A, B, and C as a new Standard Archetype Y? > there are various possibilties to deal with such needs. Firstly, it is likely that the archetype would have defined some or all of the nodes A, B, C and D as optional, meaning that any combinations such as ABC, AC, BCD etc are all legal. Specailisation is also possible. but this is for another day...it's late (or should I say early) here... Have a look at the examples linked from the ADL page at http://www.oceaninformatics.biz/adl.html if you have not already seen them. More tools are coming soon, so you will be able to look at them in ways whcih might be more natural to a clinician. - thomas - If you have any questions about using this list, please send a message to d.lloyd at openehr.org
