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AW: st: AW: Non-reported s.e. for kappa


From   "Martin Weiss" <martin.weiss1@gmx.de>
To   <statalist@hsphsun2.harvard.edu>
Subject   AW: st: AW: Non-reported s.e. for kappa
Date   Wed, 14 Apr 2010 18:26:08 +0200

<> 

" Martin-
For Karen's set up (idj contains the subject rating for  rater j),
there is no official example that I can see. p615 shows counts of
ratings, with each variable being a rating category.  Also, for p615,,
 the command should be "kappa",  not "kap","




Sure, I tweaked the thing to see whether Karen`s setup was somehow peculiar,
or whether there is simply no returned value "r(se)" for -kap- with a
-varlist- behind it. The help file seems to suggest that this value is
returned for all versions of this command...



HTH
Martin


-----Ursprüngliche Nachricht-----
Von: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Steve Samuels
Gesendet: Mittwoch, 14. April 2010 18:03
An: statalist@hsphsun2.harvard.edu
Betreff: Re: st: AW: Non-reported s.e. for kappa

Martin-
For Karen's set up (idj contains the subject rating for  rater j),
there is no official example that I can see. p615 shows counts of
ratings, with each variable being a rating category.  Also, for p615,,
 the command should be "kappa",  not "kap", because the data are
counts of assignments to three categories by five raters. This was
terrible  syntax decision: depending on the use of "kap" or "kappa" to
distinguish between two data setups.

One suggestion for a standard error:
*************************************************
version 10.0
clear
 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*
jackknife r(kappa), mse: kap id*
ci _jk_1      // First order unbiased estimates
*************************************

 n = 5 subjects doesn't seem like enough to draw many conclusions.
It's interesting that the raters disagreed for only one subject.

Steve

Steve

On Wed, Apr 14, 2010 at 10:52 AM, Martin Weiss <martin.weiss1@gmx.de> wrote:
>
> <>
>
> You do not need an imaginary dataset, as the official example does not
> return the se, either:
>
>
> *************
> webuse p615, clear
> kap cat*
> ret li
> *************
>
> The help file could make this fact clear, I think. BTW, a command
reporting
> a whole table inevitably runs into the problem which statistics it should
> return. Just see what -summ- with a -varlist- hands back: The statistics
for
> the last variable in that -varlist-. The alternative would be to return a
> -matrix-, of course...
>
>
> HTH
> Martin
>
>
> -----Ursprüngliche Nachricht-----
> Von: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Karen Wright
> Gesendet: Mittwoch, 14. April 2010 16:38
> An: statalist@hsphsun2.harvard.edu
> Betreff: st: Non-reported s.e. for kappa
>
> 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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-- 
Steven Samuels
sjsamuels@gmail.com
18 Cantine's Island
Saugerties NY 12477
USA
Voice: 845-246-0774
Fax:    206-202-4783

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