Re: st: statsby slowness

["E. Paul Wileyto" <epw@mail.med.upenn.edu>]

For large numbers of "by groups," I have found it works better/faster to 
write my own script that repeatedly pulls the original file from a 
tempfile, and then uses a keep statment to restrict the analysis.  
Statsby spends too much time looking to see who is in.

P

David Airey wrote:

> .
>
> At what point does one give up using statsby? With just three 
> variables in my data set,
>
> ssrownum, iso_VSV, expression
>
> the following command does OK with 1000 by groups (< 20 cases in a 
> group), but is not useable with 20,000 by groups.
>
> statsby n=r(N) spearman=r(rho) p=r(p), by(ssrownum): spearman iso_VSV 
> expression
>
> Why?
>
> I posted something similar a long time ago compared speeds of ttest 
> with if versus in and versus regress, but I'm not happy at the moment.
>
>
> --
> David C. Airey, Ph.D.
> Research Assistant Professor
>
> *
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--
E. Paul Wileyto, Ph.D.
Assistant Professor of Biostatistics
Tobacco Use Research Center
School of Medicine, U. of Pennsylvania
3535 Market Street, Suite 4100
Philadelphia, PA  19104-3309

215-746-7147
Fax: 215-746-7140
epw@mail.med.upenn.edu
http://mail.med.upenn.edu/~epw/ 
*
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