# Re: st: 3 equations, 2 endogenous Variables, 1 endogenous variable related to the other

 From Jason Kuruzovich To Subject Re: st: 3 equations, 2 endogenous Variables, 1 endogenous variable related to the other Date Thu, 10 Dec 2009 21:17:44 -0500

Title: Re: st: 3 equations, 2 endogenous Variables, 1 endogenous variable related to the other
After talking to some people, I think I’ve figured it out.  The code below does the estimation in several different ways and gets equivalent results.

I just thought I would post the solution in case anyone comes across the same situation.

*This example is used to demonstrate my situation.
clear
est clear
use http://fmwww.bc.edu/ec-p/data/hayashi/griliches76.dta
quietly reg3 (lw=s expr med  iq tenure) (iq tenure = s expr med age kww ), 2sls
est store reg32sls

quietly ivreg2 lw s expr med (tenure iq=kww age), first
est store ivreg2lw

*this provides a way of testing the relationship between IQ and tenure.
quietly ivreg2 tenure s expr med  ( iq=kww age), first
est store ivreg2tenure

quietly reg3 (lw=s expr med  iq tenure) (iq tenure =s expr med kww age), 3sls
est store reg33sls

quietly reg iq s expr med age kww
est store firststageIQ
rename iq iq_was
predict iq

quietly reg tenure s expr med  iq
est store secondtenure

quietly reg tenure s expr med age kww
est store firststagetenure
rename tenure tenure_was
predict tenure

quietly reg lw s expr med tenure iq
est store secondlw

estout *, cells(b(star fmt(3)) se(par fmt(2)))

*the methods provide equivalent results for the beta.