R help - Jan 2018 - What is the default covariance structure in the glmmPQL function (MASS package)?

Hello,

currently I am trying to fit a generalized linear mixed model using the 
glmmPQL function in the MASS package. I am working with the data 
provided by the book from Heck, Thomas and Tabata (2012) - 
https://www.routledge.com/Multilevel-Modeling-of-Categorical-Outcomes-Using-IBM-SPSS/Heck-Thomas-Tabata/p/book/9781848729568

I was wondering, which variance-covariance structure the glmmPQL 
function is using by default and if it is possible to vary the 
variance-covariance structure with the glmmPQL function. Unfortunately I 
couldn't manage to find out myself.
If it is possible to change it, could someone tell me how to do so? I am 
especially interested in a diagonal structure versus an unstructured 
variance-covariance structure.

Thanks a lot in advance.

Gerda

Suggestion:

Post your query on the r-sig-mixed-models list, which is (obviously)
focused on mixed models issues, and where you are likely to find both
greater interest and expertise on such matters.

Cheers,
Bert


Bert Gunter

"The trouble with having an open mind is that people keep coming along
and sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )


On Wed, Jan 31, 2018 at 1:35 AM, Gerda B?rner <gerdaboerner at gmx.de>
wrote:
> Hello,
>
> currently I am trying to fit a generalized linear mixed model using the
> glmmPQL function in the MASS package. I am working with the data provided
by
> the book from Heck, Thomas and Tabata (2012) -
>
https://www.routledge.com/Multilevel-Modeling-of-Categorical-Outcomes-Using-IBM-SPSS/Heck-Thomas-Tabata/p/book/9781848729568
>
> I was wondering, which variance-covariance structure the glmmPQL function
is
> using by default and if it is possible to vary the variance-covariance
> structure with the glmmPQL function. Unfortunately I couldn't manage to
find
> out myself.
> If it is possible to change it, could someone tell me how to do so? I am
> especially interested in a diagonal structure versus an unstructured
> variance-covariance structure.
>
> Thanks a lot in advance.
>
> Gerda
>
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