I have two questions for the list. I have been using the treatreg command
to examine a treatment effects model. I am interested in obtaining the
marginal effecets of the independent variables of all equations for the
expected value of the dependent variable. I realize that the marginal
effect of a variable is composed of the selection equation and outcome
equation. For a Heckman model, the marginal effect transformation is
dE[y| z*>0]/dx = beta - (alpha*rho*simga*delta(alpha))
where delta(alpha) = inverse Mills' ratio *(inverse Mills' ratio *
selection prediction)
The overall treatment effect employs a similar transformation using the
condition of the treatment minus the condition of no treatment.
However, how does one calculate the marginal effects for particular
variables in a treatment model?
Second, I have looked at the mfx command. There is the following for
heckman:
mfx compute, predict(yexpected)
This would give me what I am looking for, but it does not appear to be
an option for treatreg--I get the following message:
option yexpected not allowed
Any suggestions would be greatly appreciated.
Sean Bolks
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
