Calculating Quantiles (percentiles) in SAS

Percentiles can be calculated in SAS using the UNIVARIATE procedure. The procedure has the option PCTLDEF which allows for five different percentile definitions to be used. The default is PCTLDEF=5, which uses the empirical distribution function to find percentiles.

This is how the 25th and 40th percentiles of aval in the dataset adlb could be calculated, using the default option for PCTLDEF. For quantiles, Q1= 25%, Q2=50%, Q3 = 75%, Q4=100%.

proc univariate data=adlb;
  var aval;
  output out=stats pctlpts=25 40 pctlpre=p;
run;

The pctlpre=p option tells SAS the prefix to use in the output dataset for the percentile results. In the above example, SAS will create a dataset called stats, containing variables p25 and p40.