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 TM, Hauan MJ. Extending the LOINC conceptual schema to support standardized assessment instruments. J 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/20090210/7027d9fd/attachment.html>
