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  • Comparing Proportions from Samples Derived from Different Weighted Surveys

    Hi,

    I am trying to compare demographics between two weighted population surveys: Behavioral Risk Factor Surveillance System (BRFSS) and my own survey. I'm not quite sure of the correct approach of doing this since the surveys contain different weights and albeit my survey (stratified random sample) somewhat mimics the survey design of BRFSS (two stage sample design), is a little different. I tried the below syntax but receive an error message stating "estimation sample of the model saved under brfss1 could not be restored." Is there another way to compare estimates between two different surveys?

    Thanks for your consideration,
    Simone


    use brfss2010.dta, clear
    svyset _psu [pweight= _finalwt], strata( _ststr)
    svy, subpop(age>=50 & !missing(age)): reg male
    est store brfss

    use crccp.dta, clear
    svyset _n [pweight= wtfin], strata(state)
    svy, subpop(age>=50 & !missing(age)): reg male
    est store crccp


    estimates table brfss crccp, star stats(N F)
    suest brfss crccp

  • #2
    You may want to append the two data sets together, creating a source variable indicating whether the data came from BRFSS or your own survey. Create superstrata as the cross between the source and the original strata (may be as egen superstrata = group(source _ststr state), missing), and svyset the data accordingly (svyset ... [pw=...], strata(superstrata) ). Then you can svy: mean male, over(source) and test the results for differences.
    -- Stas Kolenikov || http://stas.kolenikov.name
    -- Principal Survey Scientist, Abt SRBI
    -- Opinions stated in this post are mine only

    Comment


    • #3
      Hi Stas,

      Thank you so much for your suggestions. That seems to make a lot of sense. Would I then create one variable that contains the weights ( _finalwt for BRFSS and wtfin for my survey) and the same for psu in order to svyset the data?

      Thanks again,
      Simone

      Comment


      • #4
        Hi Stas,

        That worked perfectly!! Thanks so much.

        Simone

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