You can get some help from these sites
http://www.blackwellpublishing.com/medicine/bmj/systreviews/pdfs/chapter18.pdf
http://www.medepi.net/meta/software/Bradburn_metan_updates.pdf
Olalekan Uthman
--- Long Nguyen <[email protected]> wrote:
> Hi,
>
> I'm a new user of STATA and trying to perform a meta
> regression. I would
> appreciate some detail instruction and examples or
> tutorials that can help
> me do meta regression using this new tool. I have
> the Getting Started..
> Manual and installed the metareg module; however,
> the online help file
> offered only limited information.
>
> Thank you for your kind assistance,
>
> Long
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On
> Behalf Of Brian P. Poi
> Sent: Monday, May 14, 2007 11:03 AM
> To: [email protected]
> Subject: Re: st: Different numbers of observations
> in sureg
>
> On Mon, 14 May 2007 09:16:36 -0400 Alemu Mekonnen
> wrote:
>
> > I would like to use different number of
> observations in the different
> > equations when using the seemingly unrelated
> regression command in stata
> > (i.e., sureg). For example, if there are two
> equations, I wanted to use
> > 600 observations for equation 1 and 900
> observations for equation 2. My
> > question is how do I limit the number of
> observations to do this. I was
> > not able to use the IF command but this applies to
> all the equations in
> > the system.
>
> Alemu,
>
> Allen McDowell illustrates a clever way of fitting
> the SUR model with
> unequal numbers of observations by using the -xtgee-
> command in a "From
> the help desk" article in the Stata Journal (vol. 4,
> no. 4).
>
> The trick is to recognize that the SUR model
>
> y1 = x1 * b1 + u1
> y2 = x2 * b2 + u2
>
> can be "stacked" and written as
>
> [ y1 ] = [ x1 0 ][ b1 ] + [ u1 ]
> [ y2 ] [ 0 x2 ][ b2 ] + [ u2 ]
>
> The stacked version looks just like a panel data
> model with two panels.
> One thing to note is in a SUR model, u1 and u2 are
> allowed to have
> different variances, while -xtgee- assumes they have
> a common variance.
> McDowell's article shows how to rescale the data
> using OLS regression and
> how to manipulate your dataset to use with -xtgee-.
> Then to fit the model
> you simply use -xgee- with a Gaussian distribution,
> identity link
> function, and an unstructured correlation matrix.
>
> -- Brian Poi
> -- [email protected]
>
>
> Reference
> ------------
> McDowell, A.W. (2004). From the help desk: Seemingly
> unrelated regression
> with unbalanced equations. Stata Journal, 4(4):
> 442-448.
>
>
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