Use the reference() option instead of weight(omega). The omega method
is a special case that only works with straight standard OLS, I think.
That is, do something like
cnsreg lwage ... if female==0 ...
estimates store male
cnsreg lwage ... if female==1 ...
estimates store female
cnsreg lwage ... if inlist(female,0,1) ...
estimates store pooled
oaxaca male female, ref(pooled) detail
However, is your approach with the constraints not equivalent to
applying the normalization proposed by Yun (2003)?
ben
Yun, M.-S. (2003). A Simple Solution to the Identification Problem in
Detailed Wage Decompositions. IZA Discussion Paper No. 836.
On 4/18/07, Simo Hansen <[email protected]> wrote:
Dear All,
I am using "oaxaca" program to estimate the decomposition of the gender gap.
My most important aim is to estimate the contribution of each educational
category to the gender gap. This method also provides a novel solution to
the sensitivity of the results to the choice of the reference education
category:
constraint def 1 ed1+ed2+ed3+ed4+ed5+ed6=0;
generating a variable of ones's and use the noconst option in the
regressions;
gen one=1;
cnsreg lwage one ed1 ed2 ed3 ed4 ed5 ed6 age if female==0,
noconst c(1);
estimates store male;
cnsreg lwage one ed1 ed2 ed3 ed4 ed5 ed6 age if female==1,
noconst c(1);
estimates store female;
oaxaca male female, weight (omega) detail;
I need to have some thoughts whether I am at the right track. My concern is
whether by using omega option my pooled regression is based on the following
regression:
cnsreg lwage one ed1 ed2 ed3 ed4 ed5 ed6 age for all sample
Furthermore, I want to impose another restriction on the pooled regression
model that is:
gen male=1-female;
constraint def 2 male+female=0;
cnsreg lwage one female male ed1 ed2 ed3 ed4 ed5 ed6 age, noconst c(1-2);
How can I use the parameters of the above the pooled regression model as
weights when I implement the "oaxaca programs"?
Thanks for your kind concern in advance.
Best regards,
Simo.
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