st: Interacting the treatment variable in treatreg

[rdae20@bath.ac.uk]

Hi,

I?m trying to interact the treatment term, in a treatment effects  
regression, with another variable. I?m using stata 10.
My current specification can be simplified to the equation below,  
where y1 (binary) is the treatment, being interacted with x3  
(continuous).
xt: treatreg x1 x2 i.y1*x3, treat (y1 = y2 y3)

The model seems to work, however y1 is dropped from the estimation. A  
term _iy1_1 does feature in the output, which I think represents  
(/replaces) y1, however I am not sure whether that term is the  
standard y1 variable (from the data) or the y1 predicted by the  
treatment equation.
If anybody could help, would be much appreciated?

Thanks, Richard

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