st: Predict Questions

 From "Justin G. Gardner" To statalist@hsphsun2.harvard.edu Subject st: Predict Questions Date Tue, 20 Mar 2007 10:03:03 -0500 (CDT)

```Hello Stata List,

I have a linear model:

y= d*D + b*X

Where D is a dummy variable.  Is there a simple way to generate a prediction where the dummy variable is held constant?  i.e.  I want to know what y would be if D was always 0, and what y would be if D was always 1.

I know that I can just type in two equations and generate two new variables, but that method is cumbersome if I have to repeat it several times.

What will happen if I use the predict command with and if statement?

reg y D X
predict <new variable name> if D=1

This method will only give me a prediction if D is actually 1?  If so then that is not what I need.

Justin G. Gardner
Ph.D. Candidate
Department of Agriculture and Consumer Economics
University of Illinois at Urbana-Champaign
https://netfiles.uiuc.edu/jggardne/CV
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```