Error message for weighted kappa

paola

New Member
I am working with ordinal scales for cerebral atrophy (ratings 0 to 4) and vascular burden (ratings 0 to 3) assessed by two raters. I have installed the extension bundle for weighted kappa from SPSS (version 25) but I keep getting the error message "some ratings are less than one this command is not executed". I have looked through the Internet and the IBM SPSS forum but as far as I can see nobody has come up with this problem. I know from the literature that intra- and inter-rater reliability are commonly calculated for these scales using weighted kappa. Also, weighted kappa seems to be applicable to ratings of zero in SPSS(e.g.http://www.spssusers.co.uk/Events/2015/ALDRIDGE2015.pdf) The only solution I see is recoding the ratings to avoid the value of zero but, since I would have to keep in my dataset (which is very large!) the original ratings (which are the ones that are clinically meaningful), I would end up having so many variables that it would all get very confusing and it seems a pity, especially if the error message is due to me making some mistake I am unaware of.
Any help would be greatly appreciated: my post-PhD research project is due soon and the error message is drving me mad!
Paola