Re: st: metareg with (a) std. betas and (b) sequential or stepwise?

[Roger Harbord <roger.harbord@bristol.ac.uk>]

--On 13 January 2005 05:48 -0600 "Garrard, Wendy M." 
<wendy.garrard@vanderbilt.edu> wrote:


> Is it possible to do the following with metareg?
> (a) Produce standardized betas with the metareg command?
>
> (b) Enter predictor variables in either sequential or stepwise (a.k.a.
> hierarchical) fashion? If so, must it be individual variables, or can
> blocks of variables be specified (e.g., design characteristics, then
> subject characteristics, etc.)?
>
> My meta-analysis involves mean difference (continuous) effect sizes. I
> have tried using the OLS regress options with metareg, but the only
> output I produce is error messages. For example:
> 	metareg Y X1 X2 X3, wsse(seY) bsest(reml) beta
>    or	sw metareg Y X1 X2 X3, wsse(seY) bsest(reml)
>
> Can someone advice me if I am using the wrong commands, or suggest
> effective work-arounds if these options are not available for metareg?
>
> Thanks very much,
> Wendy
Dear Wendy,

I'm currently finalising and testing an update for the user-written -metareg- 
package (including a dialog written by Tom Steichen) but i'm afraid neither 
of the facilities you mention below will be included. This may partly reflect 
a difference in common practice between medical and social sciences as 
Stata's -metareg- command was developed by those interested in medical 
applications. We don't tend to use standardised betas much and stepwise 
methods are often frowned upon - advice is often to choose a fairly small set 
of explanatory variables a priori based on subject knowledge.

However it isn't difficult to get standardised betas - simply standardise you 
predictor variables before entering them into -metareg- .
(see http://www.ats.ucla.edu/stat/stata/faq/standardize.htm )

-sw- will only work with the estimation commands listed at the top of -help 
sw-. There's no workaround other doing all the separate regressions by hand 
and looking at the output at each step.

Best wishes,
Roger.

--
Roger Harbord
Department of Social Medicine, University of Bristol
http://www.epi.bris.ac.uk

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