Thomas Beale wrote: > Grahame Grieve wrote: >> I agree with this - that's it good enough now. >> >> I think this thread is starting to talk about things which aren't >> properly part of the data type, they are conceptual things about >> the result values, and should be modelled explicitly in the archetypes. > Grahame, > > is it your feeling that we need to have a better model of accuracy, i.e. > more like the confidence interval idea? Or are we ok with what we have? > My gut feeling is to leave the current DV_QUANTITY the way it is and > consider either > a) doing nothing - treat Tim's requirements as requirements not on > primary data going into the EHR, but on generated data of the kind found > in an epidemiological/statistical style of system or
I think that is the best option, but I must point out that not all of the things I mentioned were purely of interest to epidemiologists and statisticians. I don't have time to look right now, but I am sure openEHR has the issue of normal/reference ranges for lab results well and truly covered, but the issue of the specificity/sensitivity/PPV/NPV of a particular type/method/brand of test *is* of immediate clinical interest in some circumstances, and doesn't belong only in a data warehouse. But it probably belongs in the Archetype, not the reference model. Tim C > b) add a variant of DV_QUANTITY (probably a subtype) that does the full > deal (and is convertible into a vanilla DV_QUANTITY). > > thoughts anyone? > > - thomas > >> >> Grahame >> >> >> >> >> Thomas Beale wrote: >>> >>> Sam would be better able to give an idea of all the health >>> professionals who have been consulted, but certainly in Australia, >>> Vince McCauley (a pathologist) has been extremely helpful on >>> pathology result detail. Also, people like Heath Frankel and Grahame >>> Grieve who have worked with HL7v2 messages for years have provided >>> quite a lot of input on details (for example in Release 1.0, there is >>> now a summary attribute for Historical data structures, directly due >>> to Grahame's advice on the shape of lab data his software handles - >>> see >>> http://www.openehr.org/uml/Browsable/_9_0_76d0249_1109157527311_729550_7234Report.html). >>> >>> >>> Is it enough? At this stage I would be fairly confident that the >>> models are good enough for most pathology data (certainly everything >>> any of the docs working with openEHR has seen). Are they perfect? Of >>> course not. We always need more input. The confidence level stuff >>> implied by your requirements (let's treat them as epi/public health >>> data requirements) would make things better; we just have to >>> determine a) what scope of data they apply to (e.g. how much >>> sophistication do we need in the EHR compared to say a dedicated data >>> warehouse designed for statistical studies?) and b) how to add them >>> to the current model in a way compatible with what is there. >>> >>> I think that he idea of a workshop is a good one; I would prefer to >>> see clinical professionals here take up the suggestion and do >>> something with it; I don't see these kinds of discussions as being IT >>> driven - they are all about articulating requirements. >>> >>> - t >>> >>> >>> Tim Churches wrote: >>>> Thomas Beale wrote: >>>> >>>>> 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 >>>> >>>> Not proposing anything, I'm just asking the question "Have you thought >>>> about this?" >>>> >>>> >>>>> 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). >>>>> >>>> >>>> Just curious: have you had much input from pathologists, >>>> microbiologists >>>> and lab scientists? The more one talks to such people, the more one >>>> discovers about the uncertainties inherent in certain assay techniques, >>>> and the differences in the scalar (and qualitative or Boolean) results >>>> produced by different assay kits and different labs. >>>> >>>> Oh, there's another form of uncertainty which typically is of relevance >>>> to Boolean/dichotomous results (positive/negative, detected/not >>>> detected >>>> etc) and that is the sensitivity and specificity of the test, or the >>>> related quantities PPV (positive predictive value) and NPV. (Note to >>>> computer scientists: "specificity" and "sensitivity" are cognate with >>>> "precision" and "recall".) >>>> >>>> >>>>> 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? >>>>> >>>> >>>> I think that a one or two day workshop with a range of pathologists, >>>> microbiologists, lab scientists, epidemiologists and statisticians (and >>>> some clinicians and computer scientists, of course) would suffice to >>>> come up with sensible answer to your question. I'd be happy to >>>> participate and to suggest other participants. First half day would >>>> need >>>> to be spent bringing everyone up to speed on openEHR so they understand >>>> the nature of the question(s) to be addressed (and a good means of >>>> spreading the openEHR gospel while you're at it...). >>>> >>>> Might be possible to hold a cyber-workshop instead, via email or >>>> real-time conferencing. The former would be much slower, of course. >>>> >>>> Tim C >>>> >>>> >>>> >>>> >>> >>> >> > >
