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Re: st: collapsing efficiently


From   Jenkins S P <stephenj@essex.ac.uk>
To   "'statalist'" <statalist@hsphsun2.harvard.edu>
Subject   Re: st: collapsing efficiently
Date   Thu, 18 Dec 2003 08:55:49 +0000 (GMT)

On Thu, 18 Dec 2003, Steven Stillman (LMPG) wrote:

<snip>
> This does exactly what I need but is tediously slow.  My use of egen means I
> am storing lots of unnecessary information (ie duplicate records) that I
> have no need for.
> I am pretty sure that this same idea can be used by looping over groups,
> calculating the sum, and storing this in only one observation per group.  I
> haven't been able to figure out exactly how to do this myself and am hoping
> someone else will quickly see the light here.  One problem is that summarize
> cannot be used to calculate the sum because it doesn't take non-integer
> pweights.

-help summarize- says that "aweights, fweights, and iweights are allowed;
see help weights.  However, iweights may not be  used with the detail
option."
If you have non-integer weights, then can't you use aweights or
iweights to calculate a weighted sum?  [Your weights may be interpreted
as pweights when you need to derive variances for complex survey data,
but that is not the issue here.]


Stephen
=============================================
Professor Stephen P. Jenkins <stephenj@essex.ac.uk>
Institute for Social and Economic Research (ISER)
University of Essex, Colchester CO4 3SQ, UK
Phone: +44 1206 873374.  Fax: +44 1206 873151.
http://www.iser.essex.ac.uk

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