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RE: st: RE: how to create a HLM dataset


From   mzhang@nd.edu
To   statalist@hsphsun2.harvard.edu
Subject   RE: st: RE: how to create a HLM dataset
Date   Thu, 15 Sep 2005 10:52:47 -0500

well. forget about the random counts. I use uniform distribution in my case.
And what I want to do is to know how to use stata to create a dataset with
"nested" structure. I tried to use nested loops to do this. however, it failed.
therefore I want to know how to use egen seq() to set up identifiers to achieve
this goal.

Thanks again
Min

Quoting Nick Cox <n.j.cox@durham.ac.uk>:

> -egen, seq()- could be useful for setting
> up a set of identifiers. It is of no use
> for generating random counts, however
> defined. There is a fair chunk in the
> manual entry on -egen- on -seq()-.
>
> I don't know what random counts means in the
> abstract here without any specification
> of a distribution. Alternatively, if by
> random you mean just "arbitrary" or "any
> old numbers will do", then why not
> use a real dataset instead?
>
> Nick
> n.j.cox@durham.ac.uk
>
> Joseph Coveney replied to Min Zhang
>
>
> > I'm not sure how to set up random counts of counties-within-states and
> > districts-within-counties using -egen , seq()-, but perhaps
> > the following
> > might create the data structure that your'e looking for.
> >
> > (I'm not sure whether school districts are always nested
> > within counties.
> > In any event, I believe that you can get the actual rosters
> > of counties and
> > of school districts--Nick's second suggestion--from the U.S.
> > Bureau of the
> > Census.  Check the bureau's website in the SAIPE area:
> > "Small Area Income &
> > Poverty Estimates--Model-based Estimates for States, Counties & School
> > Districts.")
>
> > set obs 50
> > generate byte state_id = _n
> > generate byte county_id = ceil(50 * uniform()) // 50 is arbitrary
> > expand county_id
> > bysort state_id: replace county_id = _n
> > generate byte school_district_id = ceil(5 * uniform()) // 5 ditto
> > expand school_district_id
> > bysort state_id county_id: replace school_district_id = _n
>
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>





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