Lenny,
p. 337 of the XT manual implies that the two are indeed equivalent. (I
find the _all group a tad bit mysterious and I intend to reread
Rabe-Hesketh & Skrondal for clarification). I'm not 100% sure what you
ran to be able to indicate why the ICC estimate was so much higher.
Jay
On Tue, Feb 26, 2013 at 11:41 PM, JVerkuilen (Gmail)
<jvverkuilen@gmail.com> wrote:
> 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)
--
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)
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/faqs/resources/statalist-faq/
* http://www.ats.ucla.edu/stat/stata/
