08-26-2016 12:59 PM
Can anyone provide or direct me to SAS code for two part models in GLM. I am analyzing cost differences between patients who have experienced a poisoning and those who have not. There are lots of zeroes in the data and it is skewed. From what I've read, the first part of the model would be a logistic regression and the second would be a regression with a gamma distribution and log link. I am especially interested in how to combine the results of the two regressions to develop estimates of cost differences between the two groups.
08-26-2016 04:24 PM
To get you started see the papers at Lexjansen.com
FYI - This is a good place to start research on any SAS topic
08-29-2016 09:49 AM
Try using PROC FMM:
Your SAS code should look something like this:
proc fmm data=rowdata;
model response = age income avgexp / dist=binary;
model response = age income avgexp / dist=gamma;
model response = / dist=constant;
The last MODEL statement specifies a constant distribution with all mass at zero for the zero target group.
To understand PROC FMM and finite mixture models take a look at: