Hi Athanasios, I doubt if mathematically measuring model complexity would be a good way to determine utility of information models for use in archetype modelling, and therefore in e-health more generally. The only way to do that is to see which ones support more / better archetypes. In this sense, the information model is like a 'theory' - the idea is to get one that is as simple as possible for the most comprehensive explanatory power.
- thomas On 10/06/2011 13:55, Athanasios Anastasiou wrote: > Hello everyone > > It has been very interesting to read the post and follow the subsequent > discussion about [the quest for] "one information model" in e-health and > especially the "patterns" part. > > I am not sure if there can be "one information model" in e-health but > what i think that can be done is a ranking of available models according > to how expressive they are and patterns (patterns of data structures and > types) would be key to this. > > For example, at the low end of the spectrum, we could have some really > simple models which are able to describe hierarchical information up to > a certain depth. For example, you can describe the data about a document > as a "sequence of element" where "element" can be "simple" (only one > data entry of some supported type) XOR "complex" (an entry composed of > many simple supported types). This would be less expressive than "a list > of element" where element can be "simple" OR "complex". In the latter > case complex elements can also be nested. Something more expressive than > this would be a "[structure] of element" where [structure] could be a > list, a tree, a graph or other of "complex" OR "simple" elements. > > The table PATTERN / EXPLANATION in Thomas' blog post is a good start but > i think that it is mixing types with some familiar class names. These > can be broken down even further: The "data/state/protocol/reasoning" is > a Dictionary. The "History of events" is essentially the same but the > type of the "index" is now different. An "order state machine" is a > directed graph (with loops). A composition document is a Set and > participations could also be sets or dictionaries. > > Could we have defined the COMPOSITION as a special case of a "set > archetype" with specific constraints? Could we have done the same for a > state machine? > > Simply counting the supported patterns would not provide a comprehensive > picture though. I trust that terms are used consistently. So, a > mathematical model provides constraints over a domain. But there is > nothing stopping someone to create an overly complex model to fit > complex data with minimal error (reminds me of feature creep). You could > have two models, one with 5 parameters and one with 50 parameters that > seem to be fitting experimental data (observations from the domain) > perfectly, which one do you choose? Obviously, the one with the 5 > parameters because it is _simpler_. Mathematics does have tools to > estimate model complexity versus how well the model describes the > observations and i am sure that some parallels can be drawn here. In > computer science, there are probably additional markers that need to be > taken into account...It's not only a matter of how expressive a model is > but also how "easy" it is to be used or how "cheap" it is to > implement...These are probably more difficult to quantify but key > factors for adopting a particular model. > > In this way, the model(s) that rank first would be the easiest and > cheapest model(s) that can describe a domain most effectively. > > We don't have a golden standard for a domain of course, but something > like this would be irrelevant. Even if we could pull all the workflows > and documents from all the healthcare systems in the world, they would > be a snapshot of what is required today** and with the exponential pace > of progress would quickly become surpassed. This means that the ranking > (without taking into account the "shape" of the domain) would only be > useful amongst two or more models. > > All the best > Athanasios Anastasiou > > **: But a very good indication of the patterns that are actually used > out there...maybe Google is already doing it. > > > > > > > > On 05/05/2011 17:20, Thomas Beale wrote: >> this is an often debated question, and after coming across (for the >> 100th time) just such a debate recently online, I thought it might be >> interesting to try to get to the bottom of the question in some way. The >> basic idea posted here >> <http://wolandscat.net/2011/05/05/no-single-information-model/>. It is >> of course not scientific work, but I would be interested in the views of >> others on this concept. >> >> - thomas beale >> ** > _______________________________________________ > openEHR-technical mailing list > openEHR-technical at openehr.org > http://lists.chime.ucl.ac.uk/mailman/listinfo/openehr-technical > -- Ocean Informatics *Thomas Beale Chief Technology Officer, Ocean Informatics <http://www.oceaninformatics.com/>* Chair Architectural Review Board, /open/EHR Foundation <http://www.openehr.org/> Honorary Research Fellow, University College London <http://www.chime.ucl.ac.uk/> Chartered IT Professional Fellow, BCS, British Computer Society <http://www.bcs.org.uk/> Health IT blog <http://www.wolandscat.net/> * * -------------- next part -------------- An HTML attachment was scrubbed... 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