The GEE Procedure

The variable in the FREQ statement identifies a variable in the input data set that contains the frequency of occurrence of each observation. PROC GEE treats each observation as if it appeared n times, where n is the value of the FREQ variable for the observation. If the frequency value is not an integer, it is truncated to an integer. If it is less than 1 or missing, the observation is not used. The frequencies must be the same for all observations within each subject.