Help with Using Lincom Command on Interaction Term

[Jason Browen]

Dear all,

I am using Stata 16, on mac. I used the following command to estimate my regression: regress wage educ urban c.educ#urban. But I wanted to use the lincom command to see what would education be if a person lived in a rural area so I tried this command, lincom educ + 0.urban + 0.c.educ#urban and got the error invalid syntax. Can the lincom command be used on c.educ#urban?

Thank you in advance for your help

Jason Browen

[Richard Williams]

urban = 0 for rural, right? So wouldn't the effect of education for people in rural areas just be the coefficient for education?

In any event, I think you want coding like this:

webuse nhanes2f, clear
clonevar wage = health
clonevar urban = female
clonevar educ = weight
regress wage educ i.urban c.educ#urban
* Effect of education for rural areas
lincom educ + c.educ#0.urban
* Effect of education for urban residents
lincom educ + c.educ#1.urban

In other words you aren't handling the interaction term correctly and you are putting the 0. in the wrong place.

[Jason Browen]

Ohhhh yeah! Thank you so very much for all of your help!