Hello everyone, I need to create a stratified sample starting from a wider population. But in creating the sample I have the constraint that I can choose observations only on a subset of the entire population. However, at the end the stratification variables should reflect the same proportions of the whole population and not of the population subset. I hope I explained. I have tried to use the proc surveyselect with the where condition but the final proportions don't reflect the whole population.   proc surveyselect data=pop_new_14_17_stima (where=(FLAG_INVIO_BFD=1)) method=sys rate=0.9 seed=1953 out=camp_new rep=1 ; strata DAT_FINE_PERIO tipo_cli_ps DEFAULT; run;   Thanks! ... View more