st: ssm with hierarchical data

[David Souther <davidsoutheremail@gmail.com>]

Hello--

I've got data on students across campuses with variables measured at
both levels, and I would like to account for the different levels of
aggregation while using -ssm-.  Currently, I'm using -ssm- to account
for the switching for a certain student treatment (it's not selection
because I observe students whether they got the treatment or not), so
the model looks like:

ssm count_truancies i_SES i_atrisk i_GPA  i_absences i_gender i_grade
c_teacherexperience c_diversity c_crime year1 year2,  ///
s(treatment =  i_SES i_atrisk i_GPA i_immigrant i_absences
c_teacherexperience  c_treatmentFUNDS ) q(16) family(poiss) link(log)
adapt

Where the DV for the main equation is a count of the number of
truancies, the switch model is determined by the dichotomous DV
treatment, and there are several individual level vars (prefix of
"i_") and campus level vars (prefix of "c_").  I've got another level
of school district data that I'd like to add to this model at some
point in the future.

Is there some way to model the different levels of data aggregation
(or some kind of hlm, xt, or clustering technique)??

Thanks in advance,
David
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