On Tue, February 10, 2009 2:22 pm, Karsten Hilbert wrote: > On Tue, Feb 10, 2009 at 02:01:59PM -0500, Greg Harris wrote: > >> Not that it's dispositive of any larger issue, but doesn't VAS >> actually record a physical quantity (specifically, the centimeter >> position on the horizontal line where the patient indicates the >> level >> of pain)? > > 7 centimeters of pain ? No, that's just a device, a > metaphor, basically. It does add a bit of comparability, > though. > > Karsten > -- The VAS is not a direct measurement of "pain." It is a direct measurement of where, on a 10 cm. line, the patient records her impression of her pain severity. So a reported VAS of 6.5 is a record that the mark the patient drew was located at 6.5 cm from the left endpoint of the pre-printed form.
There are other assessments of pain that attempt a more direct numerical measure of the pain itself. See, e.g., http://www.ispub.com/ostia/index.php?xmlFilePath=journals/ija/vol8n1/vrs.xml. But this is only a trivial point that doesn't really affect the discussion. Sorry for the distraction.
