Thank you, Mansour and professor Baum , for answering my yesterday's
question. I try to use "ivprobit" with robust and cluster. Stata would
not allow me to combine cluster and robust with twostep. Another problem
is I try to run "overid" after "ivprobit", but the error message is
"overid works only after ivreg, ivreg2". Thank you for help.
Yan IFPRI
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