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Re: st: inter-rater agreement for multiple raters and continuous variables


From   Nick Cox <njcoxstata@gmail.com>
To   "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu>
Subject   Re: st: inter-rater agreement for multiple raters and continuous variables
Date   Wed, 8 May 2013 20:50:56 +0100

I don't understand several details here.

How many variables do you expect to feed into a measure of agreement?

If each "chart" was assessed by 2 out of 3 raters, there are no
observations for which all three raters made an assessment. It seems
to follow that all you can do is cycle through the pairs of raters and
compare them.

Once you have several variables, it strikes me that an omnibus,
factotum or portmanteau measure of agreement is unlikely to be much
use.

-concord- (SJ) has been offered as a measure of agreement for
(approximately) continuous variables. I guess if this were my problem,
I would think about building up a matrix of concordance correlations.

There is stuff in the concordance correlation literature on overall
measures of agreement for several variables, but I've never been
tempted to add it to -concord-.

Nick
njcoxstata@gmail.com


On 8 May 2013 00:52, Harrison Alter <doctordad@gmail.com> wrote:
> Hello Statalisters,
>
> I am working with Stata 11.2 on a mac platform.
>
> I have a dataset of 47 patients, each with 106 variables.  Each of
> these patient's charts was abstracted by 2 raters, of a pool of 3: EL,
> SH and RO.
>
> The data are in wide format, so that each observation looks something
> like this:
>
> ID/Sex_EL /Sex_ SH/Sex_RO/DOB_EL/DOB_SH/DOB_RO
> 1001/1/./1/11.8.1955/./11.8.1955
>
> The outcomes of interest are scores on a 16-point symptom scale, and
> total drug dose in milligrams,10 outcomes in all, all continuous.
>
> I would like to calculate a measure of inter-rater agreement, focusing
> on the outcomes of interest.  I understand that kappa works best with
> dichotomous outcomes, and "loneway" seems to be appropriate for 2
> raters.  I would like to perform some measure of intra-class
> correlation.
>
> Questions:
>
> (1) Is this the right approach?
> (2) What is the right analytic test?
> (3) Can I do it in wide or must I reshape?
>
> Happy to provide any further details that might help in solving my problem.
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