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Re: st: Kappa Weights


From   Ronan Conroy <rconroy@rcsi.ie>
To   "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu>
Subject   Re: st: Kappa Weights
Date   Wed, 4 Nov 2009 10:53:27 +0000

On 3 Samh 2009, at 22:27, Jackson, Theron Keith (UMSL-Student) wrote:

I am in need of help. I am needing to calculate a kappa statistic; however, one of my raters only has one rating. Rater one has only one rating because it is the correct rating.

Rater 1  (Drug Test) 2 for positive
Rater 2 (Self-Reports) 1 for negative, and 2 for positive

Are you telling us that you have only three participants? Then the advice is to get more.

Or are you telling us that the drug test has only one rating (positive) because it is correct? In this case, your whole sample is made up of true positives. In a case like this, kappa is inappropriate. The level of agreement reduces to the proportion of self-reports (rating 2) which are positive.



Ronan Conroy
=================================

rconroy@rcsi.ie
Royal College of Surgeons in Ireland
Epidemiology Department,
Beaux Lane House, Dublin 2, Ireland
+353 (0)1 402 2431
+353 (0)87 799 97 95
+353 (0)1 402 2764 (Fax - remember them?)
http://rcsi.academia.edu/RonanConroy

P    Before printing, think about the environment




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