wrt first question
> Under the endogenous switching regime model, I need to answer two questions:
> (1) what is the overall effect of union on wage?
> ---> Is it the difference between the predicted value of wage (including
> the intercept term) for the union workers and the predicted value of wage
> for the non-union workers?
>
Yes. Although there are several possible alternatives here... you can
ask for the effect of union on a random individual with a vector X of
characteristics (what in the evaluation literature is called Average
Treatment Effect or ATE)... this is just predicting wages with the
union and the non-union equation for an individual with X
characteristics anc comparing.
Another alternative is the Average Treatment on the Treated, which
answers what is the effect of union on wages for workers who are
unionized... in this case you pick the unionized workers and predict
their non-union wage and compare...
You'll have to decide which one is of interest to you (or maybe both are).
robert duval
*
* 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/
