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From | Fred Dzanku <fdzanku@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | st: Marginal effects after heckman |
Date | Mon, 27 Sep 2010 12:53:50 +0100 |
Dear All, How can I get marginal effects of the (probit) selection equation after running a heckman selection model by maximum likelihood? I estimated a model in the form svy: heckman y $Xi, sel($Xi $Xsel) where y is the dependent variable; $Xi is a list of explanatory variables, which also appear in the selection equation; and $Xsel is a list of exclusion restrictions. I know the coefficients of the variables in the outcome equation that also appear in the selection equation must be adjusted in order for them to be interpreted as marginal effects but I also want to get the marginal effects of the selection equation. I tried the following margins, dydx(*) atmeans predict(equation(select)) vce(unconditional) but what I get as marginal effects are exactly the same as the coefficients of the selection equation. I've searched the web but have no answers yet. Can you please help or do you know how I can get some help? -- Fred M. Dzanku Dept. of Ag.& Food Econ. University of Reading PO Box 237 Reading RG6 6AR * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/