This has an overview and pointers to other work: ftp://ftp.sas.com/pub/neural/measurement.html
Some of the core measurement theory is rather mathematical - names to look out for are RD Luce, P Suppes. This Wikipedia article is not bad: http://en.wikipedia.org/wiki/Level_of_measurement Mark Mark S Leaning PhD Mob: +44 7552 747389 From: [email protected] [mailto:openehr-clinical-bounces at chime.ucl.ac.uk] On Behalf Of Sam Heard Sent: 22 April 2010 00:20 To: 'For openEHR clinical discussions' Subject: RE: ??? DV_CODEDQUANTITY Thanks Mark Any seminal papers you can point to? Cheers, Sam From: [email protected] [mailto:openehr-clinical-bounces at chime.ucl.ac.uk] On Behalf Of Mark Leaning Sent: Wednesday, 21 April 2010 6:13 PM To: 'For openEHR clinical discussions' Subject: RE: ??? DV_CODEDQUANTITY I am hesitant to enter this discussion, but here goes. An assessment scale which assigns a numeric score as well as a symbol/term is not an ordinal scale. The symbols do in fact comprise an ordinal scale ("very low" < "low" etc). However the numerics provide something else - usually to be added up with other scores. The designers of such scales are bound to validate the composite numeric scores (cf SF36). What you then have is ordinal symbol + real number. If the scale designer needs to use decimals, that is their choice. It might be worth looking at the measurement theory literature. Cheers Mark Mark S Leaning PhD From: [email protected] [mailto:openehr-clinical-bounces at chime.ucl.ac.uk] On Behalf Of Thomas Beale Sent: 20 April 2010 15:19 To: openehr-clinical at openehr.org Subject: Re: ??? DV_CODEDQUANTITY this has clearly happened because the designers of the scale did not have the term 'very very slight' in the beginning, but unfortunately they had already chosen contiguous integers. I have to say, this scale looks quite subjective. I would be amazed to discover that a) the middle terms were being used in the same way across all users or that b) the outcomes would be any worse if a 3 or 5 item scale was used instead. But I am not a doctor, so ignore that comment ;-) Practically speaking, I guess we are in the realm of having to create an ordinal kind of concept to deal with scales with retro-fitted non-integer items. A pragmatic approach might be to add a DV_ORDINAL variant called something like DV_SCALE_VALUE which is the same model as DV_ORDINAL but with the value of Real rather than Integer type. - thomas beale On 20/04/2010 12:35, Ian McNicoll wrote: Assessment scales provide a rich seam of frustration for developers, with their seemingly limitless capacity for arbitrary scales and quantities. Here is a current example about which I have been asked for advice - the Borgscale (http://www.ac6v.com/karlaz2.htm). It is a scale from 0-10, so would be ideal to express as a DV_ORDINAL but includes 0.5 which makes this impossible. There are a number of workarounds but is there a case for adding some form of Coded Quantity datatype to openEHR? The primary problem is in representing such constraints in archetypes but there might be some value in simplifying integration from Snomed coded findings. SCALE SEVERITY 0 No Breathlessness* At All 0.5 Very Very Slight (Just Noticeable) 1 Very Slight 2 Slight Breathlessness 3 Moderate 4 Some What Severe 5 Severe Breathlessness 6 7 Very Severe Breathlessness 8 9 Very Very Severe (Almost Maximum) 10 Maximum Ian -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.openehr.org/mailman/private/openehr-clinical_lists.openehr.org/attachments/20100422/0845efe1/attachment.html>
