Re: st: nonlinear growth curve in xtmixed

["josemaria" <jmpsouza@usp.br>]

Dear Stas and Maarten:
thank you for your kindness. But it seems that neither  -xtmelogit- 
nor -xtmepoisson-  nor gllamm do apply, because the response variable is 
not binary or count. For example, for -xtmelogit- the output is odds ratio. 
Rabe-Hesketh presents growth curve only in linear and quadratic polynomial 
forms.
I am interested in continuous variables, as kg, or m, or bmi (body mass 
index), that moves through time according to a logistic curve, but not a 
curve of probability from 0 to 1.
Singer & Willett use an iterative maximum likelihood procedure proposed by 
Pinheiro & Bates (Mixed-Effects Models in S and S-Plus,Springer, 2000, pages 
337-347); the response variable in Pinheiro & Bates example is the trunk 
circumference (in mm) of trees, and time is day. Each tree is measured seven 
times.
José Maria
By the way, I am not able to write anything in Mata!

Jose Maria Pacheco de Souza, Professor Titular (aposentado)
Departamento de Epidemiologia/Faculdade de Saude Publica, USP
Av. Dr. Arnaldo, 715
01246-904  -  S. Paulo/SP - Brasil
fones (11)3061-7747; (11)3768-8612
fax (11)3714-2403
www.fsp.usp.br/~jmpsouza
----- Original Message ----- 
From: "Stas Kolenikov" <skolenik@gmail.com>
To: <statalist@hsphsun2.harvard.edu>
Sent: Friday, December 12, 2008 6:54 PM
Subject: Re: st: nonlinear growth curve in xtmixed


> As of version 10, Stata provides -xtmelogit- and -xtmepoisson- for
> logistic and Poisson models, respectively. I believe Singer & Willett
> only talk about logistic models there, right? You can say those are
> nonlinear models since the mean functions are nonlinear in x's; to me
> those are extensions of generalized linear model, and hence there is
> at least some linear flavor to them. PROC NLMIXED can fit some crazy
> models with direct integration of the random effects (as far as I
> know), and full functionality of that is not available in Stata (at
> least in the easily available commands; you can write anything you
> want in Mata!)
>
> On 12/12/08, josemaria <jmpsouza@usp.br> wrote:
> > Dear Statalisters:
> >  Judith D. Singer and John B. Willet, in their book "Applied Longitudinal
> > Analysis", Oxford University Press, 2003, present, in pages 225-232,
> > analysis for nonlinear growth curve using the PROC NLMIXED of SAS, and
> > explain that, at the time of writing the book, Stata did not have yet the
> > same capability.
> >  This is also informed at the end of the page: "Stata Textbook Examples
> >  Applied Longitudinal Data Analysis: Modeling Change and Event Occurrence
> >  by Judith D. Singer and John B. Willett
> >  Chapter 6: Modeling Discontinuous and Nonlinear Change",
> >  site
> > http://www.ats.ucla.edu/stat/stata/examples/alda/chapter6 :
> >   "Table 6.6 on page 231.
> >
> >  * Skipped these for now. Stata does not yet do nonlinear mixed models." 
> > Is
> > it possible now to do such analysis in Stata?
> >  Than you for any orientation.
> >  José Maria
> >
> >  Jose Maria Pacheco de Souza, Professor Titular (aposentado)
> >  Departamento de Epidemiologia/Faculdade de Saude Publica, USP
> >  Av. Dr. Arnaldo, 715
> >  01246-904  -  S. Paulo/SP - Brasil
> >  fones (11)3061-7747; (11)3768-8612
> >  fax (11)3714-2403
> >  www.fsp.usp.br/~jmpsouza
> >  *
> >  *   For searches and help try:
> >  *   http://www.stata.com/help.cgi?search
> >  *   http://www.stata.com/support/statalist/faq
> >  *   http://www.ats.ucla.edu/stat/stata/
>
>
> --
> Stas Kolenikov, also found at http://stas.kolenikov.name
> Small print: I use this email account for mailing lists only.
>
> *
> *   For searches and help try:
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*
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