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From |
David Airey <david.airey@vanderbilt.edu> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: nonlinear growth curve in xtmixed |

Date |
Fri, 12 Dec 2008 21:27:10 -0600 |

-Dave On Dec 12, 2008, at 5:29 PM, josemaria wrote:

Dear Stas and Maarten:thank you for your kindness. But it seems that neither -xtmelogit-nor -xtmepoisson- nor gllamm do apply, because the responsevariable is not binary or count. For example, for -xtmelogit- theoutput is odds ratio. Rabe-Hesketh presents growth curve only inlinear and quadratic polynomial forms.I am interested in continuous variables, as kg, or m, or bmi (bodymass 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 procedureproposed by Pinheiro & Bates (Mixed-Effects Models in S and S-Plus,Springer, 2000, pages 337-347); the response variable inPinheiro & Bates example is the trunk circumference (in mm) oftrees, 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 xtmixedAs 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 "AppliedLongitudinalAnalysis", Oxford University Press, 2003, present, in pages 225-232,analysis for nonlinear growth curve using the PROC NLMIXED of SAS,andexplain that, at the time of writing the book, Stata did not haveyet thesame capability.This is also informed at the end of the page: "Stata TextbookExamplesApplied Longitudinal Data Analysis: Modeling Change and EventOccurrenceby 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 mixedmodels." Isit 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: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/* * 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/

* * 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/

**Follow-Ups**:**Re: st: nonlinear growth curve in xtmixed***From:*"josemaria" <jmpsouza@usp.br>

**References**:**st: pwcorr(2)***From:*Kit Baum <baum@bc.edu>

**st: nonlinear growth curve in xtmixed***From:*"josemaria" <jmpsouza@usp.br>

**Re: st: nonlinear growth curve in xtmixed***From:*"Stas Kolenikov" <skolenik@gmail.com>

**Re: st: nonlinear growth curve in xtmixed***From:*"josemaria" <jmpsouza@usp.br>

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