st: Cross-classification question

[Sarah Phillips <sfp@brandeis.edu>]

Hello All,

I am working on a project that I think requires a cross-classified approach.

My data is from 1,000 students, surveyed in approximately 200
classrooms in 1 school.  Students took the survey in at least one and
often three different classrooms-- i.e. in Math, English, and Science.
 The data set is organized such that each row is one students' survey
responses in one classroom.  So, if a student took the survey three
times, their responses would be in three different rows.  My dependent
variable is engagement, which is continuous and specific to whatever
classroom a student happened to to be in when they took the survey.
My independent variables include several student characteristics as
well as student perceptions of their teachers' classroom practices.

I believe that my data is cross-classified but I am not sure.  Most
students belong to more than one classroom in the entire data set,
which makes me think that it is cross-classified data.  But within
each observation every student belongs to just one classroom and my
dependent variable is classroom-specific, which is contrary to every
example of cross-classification that I have found.  Can any of you
shed some light on this dilemma for me?

Also, if my data is indeed cross-classified, it seems like I can deal
with this issue by adding a random-effect for class subject to my
model, since each student is only in one classroom for Math, one for
English, etc.  If so, is this the correct stata syntax for the null
model?

xtmixed engagement || _all.R.subject || classid:, mle

Or, is it:

xtmixed engagement || _all.R.subject || _all.R.classid: , mle

Thanks so much for your help!

Best,

Sarah

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