Hi,   I am analyzing healthcare costs. There are so many zero values in the data. I would prefer to use two part model. Is there anyone familiar with this model code in sas?   My outcomes is the copay for the insurance and my covariates would be the plan ID. I want to investigate the relationship between copay values and the list of covariates.   Thanks! ... View more

Hi all,   I used proc append to add observations from one sas data set to the end of another sas data set. However, I noticed the size of new dataset is much bigger than the sum of three adding data sets. I thought the size should be around the sum of three. Is there something wrong with the code?     data d.rat15to17; set d.rat15; run; proc append base=d.rat15to17 data=d.rat16; run; proc append base=d.srat15to17 data=d.rat17; run;   Thanks, Chloe   ... View more