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Re: st: statsby slowness

From   "E. Paul Wileyto" <>
Subject   Re: st: statsby slowness
Date   Tue, 14 Aug 2007 06:40:00 -0400

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.


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


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.
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