Help using Base SAS procedures

Can I specify the seed for EACH replication in Proc surveyselect?

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New Contributor
Posts: 2

Can I specify the seed for EACH replication in Proc surveyselect?

Hello there,

 

I would like to ask if there is a way to specify not only the initial seed number, but a seed for each replication when using replicate in PROC surveyselect?

The background of my question is, I want to compare two ways to do 2-stage-sampling in PROC survey select, one using replicate and one using loops. The latter results should be correct, so I have a benchmark. But as both procedures (hopefully) do the same things in different order, I cannot compare them properly with only the initial seed number. Without controlling for subsequent draws, I cannot decide if different results stem from random influences or if there is some systematic difference (i.e. some mistake).

 

PS. I had problems in sending this message, so I hope there was not double posting.

 

Thanks for your help

Birgit

Respected Advisor
Posts: 4,922

Re: Can I specify the seed for EACH replication in Proc surveyselect?

You can get initial seeds for each stratum in stratified sampling but not for each replicate in replicated sampling. So, simulate the later with the former.

 

data c;
set sashelp.class;
do rep = 1 to 10;
    output;
    end;
run;

proc sort data=c; by rep; run;

proc surveyselect data=c out=samples seed=12345 outseed sampsize=12; 
strata rep;
run;
;

data _null_;
do until(last.rep);
    set samples; by rep;
    end;
call execute(catt(
    "proc surveyselect data=sashelp.class out=s sampsize=12 seed=",
    initialSeed,
    "; run; proc append base=sample2 data=s; run;"));
run;

Samples (pseudo replicated samples) and Sample2 (samples from a loop) are the same.

PG
New Contributor
Posts: 2

Re: Can I specify the seed for EACH replication in Proc surveyselect?

Thanks so much for your help! This is very useful and time-saving.

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