Re: st: RE: [correlation structures]

["Sarah A. Mustillo" <smustillo@psych.duhs.duke.edu>]

Type -help xtgee- for a list of correlation structures.  The help file 
lists them but does not explain them.  You can do a Google search and find 
adequate explanations of the different structures.

Sarah

--On Thursday, October 30, 2003 6:47 PM +0000 Clive Nicholas 
<Clive.Nicholas@newcastle.ac.uk> wrote:


> Nick,
>
> Would love to, but don't have the documentation. I've already spent more
> than enough on software and other Stata books. :-)
>
> C.
>
> > This refers to correlation structures
> > in time. For more details, see the documentation
> > on -xtgee-.
> >
> > Nick
> > n.j.cox@durham.ac.uk
> >
> > Clive Nicholas
> > > Forgive me for being thick, but how many different 'structures of
> > > correlation' are there? I'm only aware of two: bivarate and
> > > canonical!
> > >
> > >
> > > >>> (1) I cannot successfully fit an -xtgee- model (ie,
> > > xtgee [depvar]
> > > >>> [varlist], family(binomial) link(probit) i(id)
> > > t(waves38)). All I get
> > > >>> is
> > > >>> this error message: "estimates diverging (absolute
> > > correlation > 1)
> > > >>> r(430);". Uhh? And how can this be got round?
> > > >
> > > > You don't mention what correlation structure you are
> > > specifying.  I often
> > > > have this problem when I specify unstructured correlation
> > > - which is the
> > > > most general.  If this is the case, you may solve your
> > > problem by trying a
> > > > different (appropriate) correlation structure.
> > > >
> > *
> > *   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/
>
> Yours,
> CLIVE NICHOLAS,
> Politics Building,
> School of Geography, Politics and Sociology,
> University of Newcastle-upon-Tyne,
> Newcastle-upon-Tyne,
> NE1 7RU,
> United Kingdom.
> *
> *   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/


Sarah A. Mustillo, Ph.D
Department of Psychiatry and Behavioral Sciences
Duke University School of Medicine
Box 3454
Durham NC 27710

919 687-4686 x231
*
*   For searches and help try:
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*   http://www.ats.ucla.edu/stat/stata/