Hello Thomas Thank you very much for your response.
One of the motives for what i am outlining in my last message has been the recurring discussions in the list about the suitability of this or that model (or approach) in e-health. So, an objective metric (a relative or ideally, an absolute one) of the suitability of a model to describe a domain could drive improvement and consensus. It would be the quantification of the suitability of "...[a thoery] that is as simple as possible for the most comprehensive explanatory power." Anyway, i might put together something more specific about this and share it with the list sometime later, although i admit that there are still some gray areas especially when trying to provide some practical examples on established models. All the best Athanasios Anastasiou On 21/06/2011 10:37, Thomas Beale wrote: > > 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/> > > > * > *
