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Applying a sampling weight

  • 1.  Applying a sampling weight

    Posted Fri July 30, 2021 08:43 AM
    Hi all
    I need to apply a sampling weight to my data then run a range of basic frequencies and statistics on the weighted data. I soon realised that this isn't possible in the base package so have now purchased complex samples but I'm struggling.

    I just want to apply a weight that has already been calculated. The sample isn't stratified or complex, it's just that we got greater participation in a survey from some respondents than others. The survey was originally sent out to an entire population. 

    I have created a plan file with no strata or clusters but with a sample weight added. I selected WR estimation method. 

    When I then run complex samples descriptives, the means that are produced are completely different a colleague using R. R, as I understand it just multiplies the weight by the value of the numerical variable. I can replicate the results when I do this manually in excel.

    What am I doing wrong? Any help would be much appreciated as a newbie to Complex Samples.
    Many thanks

    Claire Tyers

  • 2.  RE: Applying a sampling weight

    Posted Fri July 30, 2021 08:55 AM
    If you want simple replication or frequency weights, you can just use the WEIGHT command to set the weight variable.  For complex samples, you would have a weight variable that reflects the sampling probabilities, which is different from a replication weight.

    The CTABLES procedure gives you the option of using the weight as specified by the WEIGHT command, which is a frequency weight, or effective base weighting.


  • 3.  RE: Applying a sampling weight

    Posted Fri July 30, 2021 09:07 AM
    Hi Jon
    Thanks for your reply.
    I need to apply a sampling weight and so therefore use Complex Samples.

    I have set a plan in complex sampling to apply the weight. It seems to work well for categorical data when I use the complex sample frequencies from the drop down, but I cannot replicate my colleague's results for numerical data (means) based on her analysis in R using this approach.

    Am I doing something wrong?
    Claire Tyers
    Research Partners
    T: 01273 806466
    M: 07900 248113

  • 4.  RE: Applying a sampling weight

    Posted Fri July 30, 2021 09:36 AM
    I don't know what calculation the R code is using, but try setting the weight
    in Statistics with the WEIGHT command and running a table with CTABLES
    or DESCRIPTIVES to see if that matches the R output.

    If you can post the R code, that would help.