Tim Churches wrote: > >> Tim, if the accuracy_is_percent attribute was upgraded to a coded value, >> could you suggest a set of meanings that would cover all the epi/PH >> needs? >> > > You'll have to tell me what that would involve. A single coded value? Upper > and lower limits? Confidence level. Type of limit? > well, essentially what you are proposing would require (let's not get too pure about how I use the word "accuracy" here for the moment): - lower accuracy limit: Real - upper accuracy limit: Real - accuracy limit type: coded term - confidence level (or this could be part of the previous coded attribute, since only a small number of confidence bands are used in practice aren't they?)
Now, what we currently have is a set of general purpose quantity classes designed to enabled recording of any quantitative data we have come across so far. Between various MDs such as Sam, Vince and others, I think we have pathology covered from a practical point of view (well, we do once we get this <, >, etc thing sorted). The real question is: what is the type & origin of data that need to represented in the more sophisticated way that we are now suggesting? Is it a different category of data? Should be leave the current DV_QUANTITY as is and add a new subtype? Or is it that we should consider a quantity with a 95% T-distribution confidence interval as a pretty normal thing? Should we then start considering the "simple" idea of a symmetric accuracy range (+/- xxx) as really just one specific type of a confidence interval (it might translate to something like 98% on a normal curve). In other words, should we generalise he "accuracy" notion into a "confidence interval" notion? - thomas
