"Dennis Roberts" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] ... > some on various lists have claimed that the coefficient of variation ... ... > i have NEVER been convinced that this is so ... > does anyone out there?
FWIW, I've used coefficient of variation as a crude measure of reliability in the following context: (data are from the field of orthodonty; the article is going to be published :) several parameters (various tooth angles or their ratios - so always positive and <ratio scale> values) were measured for each subject, and each subject was measured three times (or by three orthodontists, or by three devices - I can't remember right now), and I calculated CV within each subject for each parameter, and used median CV (since many values were zero and just some about, say, 20%) across subjects as a crude measure of reliability which could then be (purely descriptively, of course) compared between parameters. Of course, this is a textbook case for which ICC methodology is apropriate, but neither the co-authors nor <leading international experts> (who heard the presentation at a conference and suggested publication in a rather prestigeous journal in the first place) were happy with that since they said in that field nobody would understand it -- the CV approach that I then thought of was just on the edge of understandable and at the same time "technical" enough to fascinate them :) Anyway, as stated in the first place, FWIW and just as an example. Which, just to tease the statistical community, can even be instantaneously and accurately implemented in Excel :) Gaj Vidmar Univ. of Ljubljana, Inst. of Biomed. Informatics . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
