Add a vertical line?

[River Huang]

Dear all, I generate a data set and estimate an interaction model as follows.

clear
set seed 123
set obs 1000
gen x = runiform() 
gen z = runiform() 
gen xz = x*z

// interaction model
gen y1 = 1+3*x-2*z+1*xz+rnormal()
reg y1 c.x##c.z, robust
quietly margins, dydx(x) at(z=(0(0.1)1))
quietly marginsplot, recast(line) recastci(rline) ciopts(lpattern(dash) lcolor(red)) yline(0)

The graph is

I wonder if we can add vertical lines, say at x=0 and x=0.5? Thanks.

[Joro Kolev]

Yes, we can:

quietly marginsplot, recast(line) recastci(rline) ciopts(lpattern(dash) lcolor(red)) xline(0) xline(.5)

[River Huang]

Dear Joro, Thanks a lot. It helps.

[Joro Kolev]

You are welcome. One more thing, both -xline- and -yline- can accept multiple space delimited arguments. Here we draw just two lines on the picture so it does not matter much, but if we are drawing many lines, multiple arguments re convenient. So the command below does the same as the command above:

 quietly marginsplot, recast(line) recastci(rline) ciopts(lpattern(dash) lcolor(red)) xline(0 0.5)

[River Huang]

Dear Joro, Got it and thanks.