* Inverse Gauss Chapter
drop _all

set seed 12345
version 3: set seed 12345
set obs 25000
generate x1 = abs(invnormal(uniform()))
generate x2 = abs(invnormal(uniform()))
generate eta = 1 + .5*x1 -.25*x2
generate mu = 1/sqrt(eta)
rndivgx mu, s(0.5)
glm xig x1 x2, family(ig) nolog

use medpar1, clear
glm los admitype codes, family(ig) link(log) nolog

xi: glm los admitype i.codes, family(ig) link(log) nolog
xi: glm los admitype i.codes, family(ig) link(id) nolog
xi: glm los admitype i.codes, family(ig) nolog
aic