I would like to estimate a model based on Cragg (1971) which contains in
a first step a probit estimation and in a second step a regression part
for all positive outcomes of the probit estimation.
I learned that I habe to estimate the second step with truncreg to
account for the truncation. Unfortunately I am working with a panel
dataset and I nowhere found a command integrating fixed/ or random
effects. Is there a possibility to do it, when not, why?
