PROC SURVEYSELECT provides several methods for random sample selection with probability proportional to size (PPS) that include PPS sampling with and without replacement. For sampling with replacement, specify the METHOD=PPS_WR option in the PROC SURVEYSELECT statement. For sampling without replacement, specify the METHOD=PPS option in in the PROC SURVEYSELECT statement. Use the SIZE statement to specify the variable that contains the size measure. 

Refer to the METHOD= documentation for additional PPS methods.