st: Test parameters across equations after ivreg2

["Susaeta ,Andres" <asusaeta@ufl.edu>]

Dear Stata members
I'm fitting the current model
ivreg2 y1 (x1 x2=a b c), robust
ivreg2 y2 (z1 z2= d e f), robust

Does anyone know how to compare the parameters across equations 
after using ivreg2? for example I want to test if coefficient of 
x1= coefficient of z1. I've tried to use test command but it 
doesn't allow me to do so.
Best

--
Susaeta Larrain,Andres


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