This article discusses how to use SAS to filter variables in a dataset based on the percentage of missing values or duplicate values. The missing value statistics can be implemented by either DATA step programming on your own or reusing the existing powerful PROC FREQ.
PROC FREQ is one of the most popular procedures in the SAS language. It is mostly used to describe frequency distribution of a variable or combination of variables in contingency tables. However, PROC FREQ has much more functionality than that. For an overview of all that it can do, see
PROC FREQ is often the first choice when you want to generate basic frequency counts, but it is the last choice when it is compared to other statistical reporting procedures. People sometimes consider PROC FREQ last because they think they have little or no control over the appearance of the
