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Re: st: reliability with -icc- and -estat icc-


From   "JVerkuilen (Gmail)" <jvverkuilen@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: reliability with -icc- and -estat icc-
Date   Tue, 26 Feb 2013 23:41:13 -0500

On Tue, Feb 26, 2013 at 9:26 PM, Lenny Lesser <lenny3200@gmail.com> wrote:
> so I did the model the way Rebecca suggested and get an ICC of 0.34
> (with Rator as a class)

> Then I did it the way you did it and got an ICC as 0.22 (with Rator
> not class, but with covariance as independent)

> I'm concerned in your model the Rator is not a class/dummy variable.

I fit the analog of the randomized block design, with random Rator but
fixed Applications.

. xtmixed Score i.Application if Rator != 4, || Rator:, covariance(identity) var



If you fit it as a class variable but omitting Rator 4 (which I just
tried) it pushes the R.Rator random effect to 0. I took Rebecca's code
(minus the little typo of Rator spelled as Rater) and simply added the
relevant if:

. xtmixed Score i.Application if Rator != 4, || _all: R.Rator,
covariance(identity)

(Notice that both models exclude Rator 4.)

These two models are statistically equivalent because they have the
same residual log likelihood. I'm not sure why the _all: R.Rator is
used here. Rebecca, could you chime in? I'm not saying you're wrong.
Sometimes there are different ways of computing the same model. (I
need to reread the manual.)


-- 
JVVerkuilen, PhD
jvverkuilen@gmail.com

"It is like a finger pointing away to the moon. Do not concentrate on
the finger or you will miss all that heavenly glory." --Bruce Lee,
Enter the Dragon (1973)
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