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From |
Stas Kolenikov <skolenik@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: growth curve model with weights |

Date |
Wed, 17 Jun 2009 12:24:34 -0500 |

Look up chapter 3 of GLLAMM manual. Section 3.2 describes the general framework for two-level random coefficient model, of which the growth model is a special case. You will have two latent factors at student level, one will be loading on the vector of 1's (the intercept), and the other one on time (the growth rate; the wave number in the simple case if they are equidistant in time... NJC, is there a proper long English word for that?). Now, you would need to add the third level, the school, on top of that, and I probably won't bother with random coefficients there, just the random intercept. Alternatively, you could move the whole random slopes structure to the school level. Finally you can have both student level and school level variability in both intercept and slope -- in -gllamm- terms, you will have four random variables set up in two-by-two structure with levels (student and school) and role (intercept and slope). Start with gen ones = 1 * assume wave takes values 1 through 4 eq intrc: ones eq slope: wave gllamm , i(student school) nrf(2, 2) eqs(intrc slope intrc slope) trace noest to get the model structure. Then you would need to constrain the coefficients (which will likely be [f1]ones, [f2]wave, [f3]ones and [f4]wave) to 1 with -constraint- command, and then add the constraints to your -gllamm- call with -constraints()- option. Now, the weights are sort of orthogonal to anything in the model structure, so you can specify them at any point. Make sure that the hierarchy of weights goes along with the hierarchy of the data. You will probably have something like gen wt1 = 1 gen wt2 = [student level weight] gen wt3 = [school level weight] gllamm ... , ... pweight(wt) On 6/17/09, P C <calicep@yahoo.com> wrote: > Thanks to Maarten and Stas. I already had these sources. But they do not have specific examples how I should handle growth curve model. I wish someone who has done that can share some experience. Thanks. > > --- On Tue, 6/16/09, Stas Kolenikov <skolenik@gmail.com> wrote: > > > From: Stas Kolenikov <skolenik@gmail.com> > > Subject: Re: st: growth curve model with weights > > To: statalist@hsphsun2.harvard.edu > > Date: Tuesday, June 16, 2009, 1:43 PM > > > See also: http://www.citeulike.org/user/ctacmo/article/850244 > > > > On 6/16/09, Maarten buis <maartenbuis@yahoo.co.uk> > > wrote: > > > > > > --- On Tue, 16/6/09, Alice wrote: > > > > I have a question about estimating growth > > curve model with > > > > survey methods in Stata. > > > > > > > > The data are logitudinal from Wave I to > > Wave IV. > > > > > > > > The sample is stratified random sample. > > Region is the > > > > strata, school is the primary sampling unit > > with weights for > > > > each individual within each wave. > > > > > > > > How should I estimate a growth curve model > > in Stata? Anyone > > > > has examples for codings? Or suggestions > > for literature that > > > > covers this topic? > > > > > > > > > You can use pweights in -gllamm-. You can read more > > about that > > > here: > > > http://www.gllamm.org/ > > > > > > -- Maarten > > > > > > ----------------------------------------- > > > Maarten L. Buis > > > Institut fuer Soziologie > > > Universitaet Tuebingen > > > Wilhelmstrasse 36 > > > 72074 Tuebingen > > > Germany > > > > > > http://home.fsw.vu.nl/m.buis/ > > > ----------------------------------------- > > > > > > > > > > > > > > > > > > * > > > * 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/ > -- 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/

**Follow-Ups**:**RE: st: growth curve model with weights***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**References**:**Re: st: growth curve model with weights***From:*P C <calicep@yahoo.com>

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