Beginning with SAS/STAT^® 12.3 in SAS^® 9.4 TS1M0, use the GROUPS= option in the PROC SURVEYSELECT statement as discussed and illustrated in this note.

Prior to SAS/STAT 12.3, use the OUTALL option in the PROC SURVEYSELECT statement to output all the original observations to the OUT= data set. The variable SELECTED in the OUT= data set equals 1 for the randomly selected units and 0 for the unselected units.

Example (for releases prior to SAS 9.4 TS1M0)

The following DATA step creates a data set with ten observations.

      data all;
        do id=1 to 10;
          output;
        end;
      run;

By specifying SAMPRATE=0.5 in PROC SURVEYSELECT, half of the observations are randomly selected. The OUT= data set, Sample, contains all ten original observations and the SELECTED variable indicates if each observation was selected (SELECTED=1) or not (SELECTED=0). The results of this example can be reproduced by specifying the same value in the SEED= option.

      proc surveyselect data=all samprate=0.50 seed=49201 out=Sample outall 
           method=srs noprint;
        run;

These statements display the Sample data set. Note that there are five observations in each of the two groups identified by the SELECTED variable.

      proc print data=Sample;
        id id;
        var selected; 
        run;

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