Hi William
We can do maths on Ordinals as long as their symbols are numeric. This is set in the archetype rather than the reference model. You will know from Bathel and Apgar that we do this. Cheers, Sam From: openehr-technical-boun...@openehr.org [mailto:openehr-technical-bounces at openehr.org] On Behalf Of Williamtfgoossen at cs.com Sent: Wednesday, 11 February 2009 7:27 AM To: openehr-technical at openehr.org Subject: Re: CQuantityItem.units not empty Thomas wrote: In a message dated 10-2-2009 18:21:06 W. Europe Standard Time, thomas.beale at oceaninformatics.com writes: As far as I can see, the current openEHR data types satisfy your needs (with one exception - see below): DvQuantity - handles all PQ, including with no units DvOrdinal - handles all ordinals, with any kind of symbols, including from coding systems I don't understand the need for summations etc for ordinals, because the general nature of ordinal values is that that symbolically identify arbitrary ranges in a value space (e.g. amount of pain, amount of protein in urine etc). Mathematically they don't satisfy the requirements to be summable. Can you explain further the intended semantics here? William: That is perfect and will help deal with the VAS and numeric and base ordinal. The exception is that neither of the above types handles a non-integral 'ordinal' idea. Hence my proposal of DV_SCORE. There are probably better solutions, I have not thought much about it. I do think however, that any solution needs to be mathematically sound, because downstream data computing relies on that. The mathematical requirement of summation is a clinical necessary feature for about a 1000 to 10.000 assessment scales used in a variety of clinical domains. The generic feature is that an ordinal scale is used as a value for a variable, so per node the value can be e.g. 0 = no problem, 1 = some problem and 2 = severe problem the semantics is clear and indeed an ordinal scaling. However, ususally assessment instruments / scales / indexes of scores consist of more than one variable. E.g. Apgar score has 5 variables, with a minimum score (worst case) = 0 and a maximum score (best case) = 10. Similar scales include Barthel, Glasgow coma scale, Braden etc. So the summation as mathematical approach is as follows (using the following explanation to the scores: 0 = no problem, 1 = some problem and 2 = severe problem). variable 1, score = 1 variable 2, score = 0 variable 3, score = 2 variable 4 score = 1 variable 5 score = 0 variable 6, score is 0 Total score on the instrument is score variable 1 + score variable 2 + score variable 3 + score variable 4 + score variable 5 + score variable 6 = 1 + 0 + 2 + 1 + 0 + 0 = 4. This is usually viewed agains scientifically derived reference ranges, e.g. 4 out of 12 (maximum for 6 variables is So for appropriate scales / indexes etc the mathematics need to be possible on the ordinal values. See for a discussion on these features e.g. White <http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22White %20TM%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel. Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus> TM, Hauan <http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Hauan %20MJ%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel. Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus> MJ. Extending the LOINC conceptual schema to support standardized assessment instruments. J <javascript:AL_get(this,%20'jour',%20'J%20Am%20Med%20Inform%20Assoc.');> Am Med Inform Assoc. 2002 Nov-Dec;9(6):586-99. Would you agree with my understanding of the problem as stated here? - thomas Sincerely yours, dr. William TF Goossen director Results 4 Care b.v. De Stinse 15 3823 VM Amersfoort the Netherlands email: Results4Care at cs.com phone + 31654614458 fax +3133 2570169 www.results4care.nl Dutch Chamber of Commerce number: 32133713 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.openehr.org/mailman/private/openehr-technical_lists.openehr.org/attachments/20090212/5c0c1849/attachment.html>
