--- Sarah Gill wrote:
> I am trying to run 2 categorical interaction terms with a common
> variable (agegroup) in a gllamm model (see below), and get the error
> message "variables have been dropped, can't continue". I assume this is
> due to collinearity because of the common variable - is there anyway to
> get around this and still be able to estimate these interactions?
>
> xi: gllamm dv time i.sex i.agegroup*smoke i.agegroup*drink, i(id)
> link(logit) family(binom) nrf(2) eqs(inter slope) robust
Make the dummies and interactions yourself or:
xi: gllamm dv time i.sex i.agegroup*smoke i.agegroup|drink, i(id)
link(logit) family(binom) nrf(2) eqs(inter slope) robust
Hope this helps,
Maarten
-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands
visiting address:
Buitenveldertselaan 3 (Metropolitan), room Z434
+31 20 5986715
http://home.fsw.vu.nl/m.buis/
-----------------------------------------
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