Mr.beale Please take me off you email list. I have not been this filed for 5 years. Thanks
Sent from my iPhone > On Jun 11, 2016, at 6:09 AM, Thomas Beale <thomas.be...@openehr.org> wrote: > > Let's state the problem as one of associating some sort of absence, presence, > or in-between indicator with some X in a patient, or some other subject... > > There is some discussion about this topic in SPECPR-118, in which Ian > McNicoll made the comment: > > I think we need to do a bit more thinking about the pros and cons and the > somewhat different requirements of e.g negating a diagnosis vs. negating a > symptom. > > This is exactly right - there are different kinds of Xs. There are observable > Xs, including things we use instruments to observe (which we generally assume > to be reliable in a practical sense). So presence/absence claims can > reasonably be made in cases where the X being observed (e.g. pregnancy, MRSA, > being a smoker) is the same thing the claim is made about (is pregnant, neg > MRSA, non-smoker). In this case, the presence / absence can reasonably be > said to be part of the reported reality of the X in question. > However, if the claim is about a C (some 'condition') where C cannot be > directly observed (or is not, in the current situation) then we are looking > at an epistemic claim about knowledge of C, based on observed X, what X means > in the context of patient type P, and so on. There is a range of epistemic > claims that could be made about Cs, e.g. the following: > doesn't exist - 100% sure C not present in patient - e.g. diabetes type I, > based on negative oral glucose test > may exist - C is effectively one branch of a differential diagnosis or other > assessment > does exist - 100% sure C present in patient - e.g. diabetes type I, based on > +ve oral glucose test > no risk of C in future - 100% sure C will not occur, e.g. BRCA1 or 2 breast > cancer, based on genetic test (we assume the latter is bullet-proof) > risk of C in future - some likelihood of C occurring > guarantee of C occurring in future - future reaction to exposure to bee venom > in a patient known to be hyper-allergic to been venom > This basically boils down to: > > it may be reasonable to allow presence or absence of true 'observables' to be > encoded in a binary way (what we think of as Observations in openEHR) > claims regarding any kind of assessment, opinion, diagnosis, etc of something > we don't directly observe as such are epistemic claims, i.e. claims about > type of knowledge we have of some C, and are not encodable as a Boolean > 'existence' idea, but only as a level of certainty or similar. (what we think > of as Evaluations in openEHR) > To make things somewhat annoying, there is probably a grey area between the > two. For example, 'pregnant' could arguably be regarded as a direct > observation or an assessment. But I think for 95% of cases things are obvious. > So my conclusion is that the way to record presence / absence of true > observables could reasonably be done in a simple way, while any type of > assessment has to be recorded in a way that a) allows some range of > certainty, b) can include the temporal aspect (now, future etc) and c) can > reflect the current state of the investigative process. > > Another annoyance that may prevent simple modelling is that EHRs often > include statements like 'is diabetic', e.g. reported by an obviously diabetic > patient about her diagnosis from 20y ago. Such statements are not in > themselves assessments, they are reports of the outcome of an earlier > process. As such, it may be reasonable to report such things in a more or > less binary way, e.g. is / is not diabetic. > > I'm not a fan of negation or any other variety of presence, absence, risk of > etc being part of terminology, at least not pre-coordinated with the > ontological part (doing so is a total confusion about what the terminology > expresses). A typology of negation / epistemic claims could potentially exist > in some separate part of a terminology e.g. SNOMED, to be used to code > information model property like 'epistemic_status', or similar. > > Aside: apparently the FHIR approach to representing things like 'no known > allergies' is to infer it by seeing if an allergies list is empty or not. > That sounds like a bad idea to me. If 'no known allergies' is understood as a > clinically meaningful statement made by e.g. a GP (based on reliable > knowledge about the patient), checking for a list being empty in some EMR > system isn't at all the same thing. All that latter does is establish that no > allergies have been recorded on this particular system. > > - thomas > >> On 08/06/2016 07:54, GF wrote: >> >> >> Dear Colleagues, >> >> HL7 is thinking about the problem of negation. >> http://wiki.hl7.org/index.php?title=Negation_Requirements >> The group discussing it created a document with negation use cases. >> >> My questions are: >> - Can you let us know your reaction to this list of use cases? >> And >> - How should ‘negation’ be handled the best in respect of semantic >> interpretability? >> >> My personal opinions: >> - the boolean should not be used >> - try to translate the ‘negation’ problem into ‘presence and absence’. A >> concept is or is not present, a numeric result is of is not present. >> - do not use pre- and post co-ordinated concepts using SNOMED but use the >> SNOMED primitives. >> >> I’m curious to learn what your opinion is. > > _______________________________________________ > openEHR-clinical mailing list > openEHR-clinical@lists.openehr.org > http://lists.openehr.org/mailman/listinfo/openehr-clinical_lists.openehr.org
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