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Re: st: Multistage sampling svyset


From   Steve Samuels <sjsamuels@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Multistage sampling svyset
Date   Thu, 10 Jun 2010 15:04:56 -0400

James, what is "pi4"? What is the variable which identifies the
community?  How did you compute the sampling weight "pwgt"?  (show an
example, as well as code.)

Steve


On Thu, Jun 10, 2010 at 2:33 PM,  <James.Valcour@med.mun.ca> wrote:
> I'm having a problem using the survey commands to analyzing a survey
> that used a complex sampling design.
>
> Eleven communities were sampled (these were all the communities in the
> study area).  Within each community households were randomly selected
> from all available households.  Within each household one person was
> randomly select from all members of the household that were eligible to
> be in the survey (we had a list of everybody eligible in the house).
>
> This is the code I used to set the data:
>
> svyset houseid [pw=pwgt], strata(pi4) fpc(p_household) || _n,
> fpc(p_person)
>
> where
> houseid is an identifier for the house in the community; a mix of the
> community id number and the house number
> pi4 is an identified for the community (1-11)
> p_household is the probability of selection of the household in the
> community
> p_person is the probability of selection of the person in the household
>
> The problem I'm getting is when I'm trying to estimate the proportion of
> study with certain ailments.  I'm not getting confidence intervals
> included in the estimates.  The message that is given is " Note: missing
> standard errors because of stratum with single sampling unit."
>
> I've tried other ways of specify the svyset command and tried
> simplifying to the point of just assuming that household were sampled
> but I get the same error.  (for the record here's that command "svyset
> _n [pw=pwgt], strata(pi4) fpc(p_household)")
>
> Any help would be appreciated,
>
> Thanks!
> James Valcour
>
> --
> Dr. James Valcour
> Division of Community Health and Humanities
> Faculty of Medicine
> The Health Sciences Centre
> Memorial University of Newfoundland
> St. John's, NL, Canada
> A1B 3V6
> Tel:  709-777-2237
> Fax: 709-777-7382
> Email: james.valcour@med.mun.ca
>
>
>
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>



-- 
Steven Samuels
sjsamuels@gmail.com
18 Cantine's Island
Saugerties NY 12477
USA
Voice: 845-246-0774
Fax:    206-202-4783

*
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