st: Non-reported s.e. for kappa

["Karen Wright" <Karen.Wright@icr.ac.uk>]

Dear All,
I have been working with kappa statistics and I have come across a peculiarity that I don't fully understand.  Searching the help files and the statalist archive did not shed any light on the matter unfortunately.
After running a simple composite kappa on multiple readers (3 categories)  I then type -di r(se)- and obtain nothing!  The results have not been cleared from memory as typing -di r(kappa)- displays the kappa value.  Does anyone know why this is?
I am aware that test statistics cannot be calculated when the number of ratings per subject vary.  Is there something similar happening here?!

I have shown below a snippet of the data and the commands used.  Snippet of data contains the diagnosis (=1,2, or 3) for 6 readers (id2-id10) on 5 cases.  [Done using Stata10 on Windows.]

Thank you for taking the time to read this,
Karen

*************************************************
version 10.0

input case id2 id3 id6 id8 id9 id10
1 3 3 3 3 3 3
2 1 1 1 1 1 1
3 2 2 1 3 1 1
4 3 3 3 3 3 3
5 1 1 1 1 1 1
end

kap id*
di r(se)
di r(kappa)

*************************************************



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