Retreiving AIC value after estat ic

[Sandra AJ Alba]

Hi all,

I'd like to save the AIC values of a number of models in a dataset. I have the following code below. But I am not actually getting the AIC value like this, the local remains empty... Can anyone help?

Thanks!

Sandra

foreach var of varlist rural_wb-bcg{
use prev_allcov_4model, clear
quietly xtmelogit bc `var' || iso3: , binomial(n) or
estat ic
regsave using xtmelogit_`var', replace
use xtmelogit_`var', clear
local aic=s[1,6]
gen aic=`aic'
gen model="`var'"
save xtmelogit_`var', replace
use prev_allcov_4model, clear
}

[Mike Lacy]

-regsave- is a user-written package from ssc, not a built-in feature of Stata.

Its help file indicates that it "fetches output from Stata's e() macros, scalars, and matrices and stores them in a Stata-formatted dataset." The AIC value from -estat ic- is returned in r(), not e(), so your -regsave- would not have stored it. Also, -estat- does not creat a matrix named "s" as your code assumes, but rather returns one in r(S). You can access elements of r(S) by assigning it a matrix s = r(S), and then referencing them, as you do, as s[1,6]

All this being said, I would use the built-in command -postfile- for your purposes.

Regards, Mike

[Sandra AJ Alba]

Thanks Mike! Also I had estat in the wrong place. Just in case it is useful for others, this code works

foreach x in `vars' {
use prev_allcov_4model, clear
xtmelogit bc `x' || iso3: , binomial(n) or
regsave using xtmelogit_`x', replace
use xtmelogit_`x', clear
estat ic
mat s=r(S)
local aic=s[1,6]
gen aic=`aic'
gen model="`x'"
save xtmelogit_`x', replace
use prev_allcov_4model, clear
}

[Rhys Williams]

A bit late to the party, but just to clarify, for anyone referring to this problem -s[1,6] accesses the Bayesian Information Criteria entry and not the AIC, this would be s[1,5]

Best,
Rhys