Hello -
I have a question about pweights and the multilevel model (MLM) command -gllamm-. I have put together a simple MLM using -gllamm- that involves 2 levels (schools and individuals) which runs and presents reasonable data.� I am having difficulty though when I add in the probability weights.� Sampling was somewhat complex for the data set I am using but for my purposes, I have pweights only for individuals.� Sampling was not done at the level of the schools.� School-level data were collected where each study participant attended.� I have used the -pwigls- command to adjust my survey weights for MLM analyses.�
My questions are:
Is it possible to do a MLM analysis with a level which was not sampled?�
If so, is there a way to incorporate weights for a non-sampled level (such as schools in this case) so I am not relying on an unweighted analysis?�
I have tried using a wt = 1 for all schools and "adjusting" the pweights using -pwigls- for the individual level. I am not sure if it is correct.
I have not been able to find the answer to these questions from the help command for -gllamm- and -pwigls-, www.gllamm.org, and the book on this command entitled "Multilevel and Longitudinal Modeling Using Stata." I have not heard back from a direct email to the -gllamm- authors.
Thank you in advance for your time in considering this issue.
Sarah
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