Re: st: how to handle clustering

["Michael N. Mitchell" <Michael.Norman.Mitchell@gmail.com>]

Dear Kate

  My feeling is that a multi-level model is still an appropriate model, because you have 
data at the child and classroom level, with the predictor (intervention) at the classroom 
level and the outcome at the child level.

  In any case, I do not feel you will derive more power from using -regress- with 
-vce(cluster classroom)- than you would from using -xtmixed .... || classroom:- . In both 
cases, the standard errors reflect the correlation of observations within classrooms, but 
with the multilevel model I feel you would have the opportunity to more clearly formulate 
the model in terms of child level and classroom level predictors.

I hope that helps,

Michael N. Mitchell
Data Management Using Stata      - http://www.stata.com/bookstore/dmus.html
A Visual Guide to Stata Graphics - http://www.stata.com/bookstore/vgsg.html
Stata tidbit of the week         - http://www.MichaelNormanMitchell.com



On 2010-07-29 8.36 AM, Kate Welti wrote:
> Hello,
>
> I am analyzing data in which I have treatment and control classrooms
> (intervention was at the classroom level) and child-level test scores.
>   Ideally, I would use a multi-level model, however, I don't have
> enough classrooms and children to do so (according to a power
> analysis).  I need to find a way to control for the clustering of
> children in classrooms.  Can Stata's cluster option be used in this
> instance?
>
> Thanks,
>
> Kate
>
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