Thank you Joseph.
That is exacly what I needed.
Ricardo
Ricardo Ovaldia, MS
Statistician
Oklahoma City, OK
--- On Wed, 7/22/09, Joseph Coveney <[email protected]> wrote:
> From: Joseph Coveney <[email protected]>
> Subject: Re: st: correlation for longitudinal data
> To: [email protected]
> Cc: [email protected]
> Date: Wednesday, July 22, 2009, 11:31 AM
>
> Ricardo Ovaldia wrote:
>
> Is there a way to estimate a correlation coefficient of two
> continuous
> measurements each collected over time on a sample of
> patients? Not sure if I can
> do this with -xtreg- for example.
>
> --------------------------------------------------------------------------------
>
> I think that you're asking about a multivariate measurement
> over time, such as
> left eye intra-ocular pressure and right eye intra-ocular
> pressure during
> treatment for glaucoma; you want to estimate the
> correlation of intra-ocular
> pressure measurements between eyes over time in a group of
> patients. Or
> something analogous, such as what's the correlation between
> physiological
> measurements made by a novel method and the conventional
> method in a group of
> patients undergoing a period of evaluation for some
> disease.
>
> You can do that with -xtmixed-. Take a look at the
> discussions and
> illustrations of various types of intraclass correlation
> coefficients in S.
> Rabe-Hesketh & A. Skrondal, _Multilevel and
> Longitudinal Modeling Using Stata_
> (College Sta., Texas: Stata Press, 2005 or 2008).
> There are several places in
> the first edition (which is what I have) where the topic is
> covered, and I
> assume that the second edition does, too.
>
> Joseph Coveney
>
>
>
>
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