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Re: st: RE: RE: generating a new variable with the egen command


From   agostino@unical.it
To   statalist@hsphsun2.harvard.edu, Maarten Buis <M.Buis@fsw.vu.nl>
Subject   Re: st: RE: RE: generating a new variable with the egen command
Date   Mon, 28 Nov 2005 16:43:15 +0100

Thank you very much for all your answers!
Best
Mariarosaria

Citazione Maarten Buis <M.Buis@fsw.vu.nl>:

> Furthermore, calculating the sums in float format isn't as bad as it
> initially seems: the fact that Stata shows only 3 digits of precision has to
> do with the display format. The float is precise up to 8 digits, and is
> stored that way, as can be seen in the program below.
> 
> *-------------------------example------------------
> drop _all
> input x
> 	42224464
>       67090781
> end
> 
> egen sum = sum(x)
> egen long sumlong = sum(x)
> 
> list sum sumlong 
> 
> format sum %20.7g
> 
> list sum sumlong
> *------------end example-----------------
> 
> HTH,
> Maarten
> 
> 
> -----------------------------------------
> Maarten L. Buis
> Department of Social Research Methodology 
> Vrije Universiteit Amsterdam 
> Boelelaan 1081 
> 1081 HV Amsterdam 
> The Netherlands
> 
> visiting adress:
> Buitenveldertselaan 3 (Metropolitan), room Z214 
> 
> +31 20 5986715
> 
> http://home.fsw.vu.nl/m.buis/
> -----------------------------------------
> 
> -----Original Message-----
> From: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu]On Behalf Of Nick Cox
> Sent: maandag 28 november 2005 16:42
> To: statalist@hsphsun2.harvard.edu
> Subject: st: RE: generating a new variable with the egen command
> 
> Your call should be
> 
> egen double newvar = ...
> 
> or
> 
> egen long newvar = ...
> 
> If these are integers, -long- is better. Either type
> is allowed by the syntax. See the help for -egen- once more.
> 
> Nick
> n.j.cox@durham.ac.uk
> 
> >agostino@unical.it
> >
> > I'm trying to generate a new variable given by the sum of an
> > existing variable
> > by year (as I have 2 six month observations for the same
> > year) and individual.
> > The command is the following:
> > egen newvar=sum (oldvar), by(id year)
> >
> > the problem is that the original values are, for instance:
> > 42224464 and
> > 67090781, but the sum that STATA computes is 109000000,
> > instead of 109315245.
> > Why does it round like that?
> > The old variable is stored as "double", I have tried to
> > change the storage
> > type, using recast, but STATA does not allow to do it, as
> > many values would be
> > changed...
> 
> 
> 
> *
> *   For searches and help try:
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> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/
> 




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