Hi,
This is the standard -heckman- example from the -help- menu using the
-twostep- procedure:-
webuse womenwk
heckman wage educ age, select(married children educ age) twostep
Suppose I want to take it one step further and predict the personal
wealth of women. This is not the best example, but it should be
somewhat clear as to what I am trying to achieve.
Let's assume "hours" (i.e. hours worked) is another variable in the
dataset and takes on a value only for women who earn a wage.
I then create an interaction term with "wage".
gen wagehrs = wage*hours
I need to run the following model:-
wealth = f(wage, hours, wagehrs, control variables)
I have data on the variable "wealth" and the control variables for
women who earn a wage AND women who don't.
Can someone please help me to model the above? Basically, I am not
clear if I need to run -heckman- once (as above) or twice? (ignore the
economic relevance or otherwise of the "wealth" regression since it is
merely for illustration purposes)
Thanks,
--
Hugh
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