Thomas, after reading your last message, I think GEHR and HL7v3 is very much on the same side. In fact, we already converged: GEHR came to include more specificity and HL7v3 has recently gone towards more generality. So, we now agree on the three level approach towards clinical information: (1) One concrete data structure information model, mostly graphically rendered in BON or UML. (Actually, if your BON-bubbles would show the attributes, and if the association lines were not so ugly double-fat, I would have no problem with using BON instead of UML. But not seeing the attributes is a real problem.) (2) Thousands of what both GEHR and HL7 call "templates" defining clinical collections of information. (3) A knowledge base (also called "master files," or "data dictionary") that define the observations, normal ranges, dosage instructuions, defaults, and those templates. Both GEHR and HL7 v3 have these three layers. I have not seen how GEHR maintains the knowledge layer and how GEHR maintains template definition. (I'm going to dis-regard the mentioning of XML DTD's in GEHR as a to-be revised mistake... this marketing hype makes all of us weak, I know. :-) In HL7 we have traditionally spoken of "master files" and still do so. But my vision has been to remove "master" tables from the model and merge them into the instance tables ... in your words, my belief is that a priori predicates and a posteriori predicates do have the same structure and that the semantic difference can be factored into a single code, which we call the mood code. Furthermore, I don't believe that subjective and objective a-posteriori predicates are structurally any different, in fact I even don't see the semantic difference, since there is nothing that reliably distinguished subjective from objective observations. Only circumstances (like who reported?, who witnessed?) that may make the distinction. Just try to label these as subj. vs. obj.: "HEART MURMURS", "PALPITATION", "PULSUS CELER ET ALTUS", "SCHIZOPHRENIA", "HALLUCINATIONS". What are your criteria? So, in HL7 v3 we do not make these distinctions in the concrete information model. Instead we represent all this attribution information with the medical record item, which we call Service. We believe that the professional action (Service) is in the center of the medical record. We believe that observations are just a specialization of actions (and hence I renounce CORBAmed's COAS, if only for it's name.) We also believe that the notion of Service Action is more powerful to standardize meaning than the concept of "Record Item". Everything can be an "item" but not everything should be a distinguished Service in HL7 ... at least what this Item/Service thing generally does should be clear without digging in a semantic network of 100000 entries. My favorite example for a non-observation and more-than-an- item is our Medication class with it's attributes. These allow you to express/share medical prescription data have in a stricly defined way, rather than having to make up bogus codes (or "headings") we use static attributes where we can. Table-drivenness is not a benefit in itself, we use it only if we have to. We have to for many things, but when it comes to largely quantitative phenomena, we may be able to do better. Some questions: is the home of GEHR Australia now and are you the chief modeler? Who else is in the GEHR group? What are your relationships to Europe and CEN's EHCRA (honestly, no fluff please)? Why has GEHR and EHCRA, who are so similar, been developed in two separate branches? If you track HL7 v3 work, would you be interested in sharing and getting into further collaboration to converge? Can you come to HL7 meetings? HL7 Australia (contact Klaus Veil or Dawid Rowed) may assist you in this effort. How married are you to Eiffel? It seems like a lot. I don't see Eiffel to become mainstream, even though it certainly is better than Java, it may be a path that leads into isolation. How well is GEHR portable onto other things than Eiffel, ... I know, you can always map, but impedance mismatch may render a good model difficult in another environment. Finally for now: what happened to the Units of measure between GEHR 1.0 and GEHR 2.2? Is it gone? Why? Are you interested in a replacement? regards -Gunther -- Gunther_Schadow-------------------------------http://aurora.rg.iupui.edu Regenstrief Institute for Health Care 1050 Wishard Blvd., Indianapolis IN 46202, Phone: (317) 630 7960 [EMAIL PROTECTED]#include <usual/disclaimer>
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