When any of the CERTSIZE options are used with METHOD=PPS or METHOD=SAMPFORD on the PROC SURVEYSELECT statement, if the number of certainty units equals the specified sample size in any stratum, then the resulting sample from that stratum will be incorrect. The output sample data set will contain the first N units of the stratum, where units are ordered by size for METHOD=PPS and are in input order for METHOD=SAMPFORD, instead of the N certainty units. The following log message is issued:

  NOTE: The number of certainty units equals the specified sample size.

but there is no indication that the sample is wrong.

There is no circumvention for this problem. The certainty units will have to be manually selected for strata where this occurs.