When a stratified random sample is selected in the SURVEYSELECT proceedure, the following log message might incorrectly indicate that too few observation were read from the input data set:
NOTE: There were <N> observations read from the data set <Data Set Name>.
In this situation, PROC SURVEYSELECT is using the correct number of observations from the input data set and the NOTE should be ignored. When a SIZE variable contains missing or nonpositive values, those observations are excluded from the sample selection. Otherwise, the procedure is reading the entire input data set.