clear
set obs 500
generate x1 = runiform(-3,3)
generate x2 = runiform(-3,3)
generate y = invlogit(x1+x2)> runiform()

logit y x1 x2
local B1 = _b[x1]
local B2 = _b[x2]
logit y x1

regress x2 x1
local T2 = _b[x1]
local BT2 = `B2'*`T2'
local check = `B1' + `BT2'

predict x2r, resid
logit y x1 x2r

display "Total: " _b[x1]
display "Direct: " `B1'
display "Indirect: " `BT2'
display "Total check: " `check'

*khb logit y x2 || x1
khb logit y x1 || x2

clear
set obs 500
matrix C = (1, .5 \ .5, 1)
drawnorm x1 x2, n(500) corr(C)

generate y = invlogit(x1+x2)> runiform()

logit y x1 x2
local B1 = _b[x1]
local B2 = _b[x2]
logit y x1

regress x2 x1
local T2 = _b[x1]
local BT2 = `B2'*`T2'
local check = `B1' + `BT2'

predict x2r, resid
logit y x1 x2r

display "Total: " _b[x1]
display "Direct: " `B1'
display "Indirect: " `BT2'
display "Total check: " `check'

khb logit y x1 || x2

gsem (y <- x1 x2, family(binomial)) (x2 <- x1)