--- Barth Riley <[email protected]> wrote:
> I am running a multilevel logistic model using gllamm. In addition to
> estimating fixed and random effects, I am using the geqs() option to
> fit a regression model to predict the second-level latent variable. I
> am encountering two problems: (1) even after 200+ iterations, gllamm
> fails to converge in estimating the fixed effects, even though the
> estimated coefficients remain unchanged throughout most of the
> iteration cycle; and (2) I received the error "unable to estimate
> maxmimum likelihood" during the estimation of the geqs() model
You are trying to do a lot in a single model. As a general modeling
strategy I would start simple and build the model by adding one
complication at a time. That way it is much easier to diagnose any
problem. I often don't practice what I preach, and I often start with
estimating a much too complicated model. However, whenever I run into
trouble (i.e. always) I diagnose the problem by going back to a simple
model and building the complicated model by adding one complication at
a time.
Are you trying to estimate the fixed effects by adding dummies (e.g.
the variables d1_1-d17_1)? In that case you are getting inconsisten
estimates, see:
http://www.stata.com/statalist/archive/2007-10/msg00935.html
-- Maarten
-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands
visiting address:
Buitenveldertselaan 3 (Metropolitan), room Z434
+31 20 5986715
http://home.fsw.vu.nl/m.buis/
-----------------------------------------
___________________________________________________________
Yahoo! Answers - Got a question? Someone out there knows the answer. Try it
now.
http://uk.answers.yahoo.com/
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
