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Re: st: gllamm dropping variables


From   Stas Kolenikov <skolenik@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: gllamm dropping variables
Date   Thu, 21 Mar 2013 10:16:16 -0500

Does this lead to a perfect prediction? At any rate, for random effect
logistic models, I would use -xtlogit-, as it is faster, and probably
more stable, than -gllamm-.

-- Stas Kolenikov, PhD, PStat (SSC)
-- Senior Survey Statistician, Abt SRBI
-- Opinions stated in this email are mine only, and do not reflect the
position of my employer
-- http://stas.kolenikov.name



On Thu, Mar 21, 2013 at 10:02 AM, Bontempo, Daniel E <deb193@ku.edu> wrote:
> I have some dummy codes for levels 2 and 3 of a 3-level group variable. With xtmixed, I can use i.group, but with gllamm I have to make dummy codes.
>
> The codes work fine when I run a linear model, but cause the variables to drop when I use link(logit)
>
> This runs fine:
> gllamm regPart ae le, i(number) adapt
>
> This won't start:
> gllamm regPart  ae le, i(number) adapt family(binomial) link(logit)
> variables have been dropped, can't continue
> r(198);
>
> I assume the variables are dropped for collinearity, but do notunderstand why.
>
> BTW, using glm seems to have no problem:
> glm regPart ae le, link(logit) family(binomial) cluster(number) eform
>
>
> If I use a continuous IV with gllamm it will also run. Why are my dummy codes being dropped?
>
>
>
>
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