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Re: st: RE: possible to combine nmissing with tabstat?


From   "A.M. Vos" <a.vos@erasmusmc.nl>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: RE: possible to combine nmissing with tabstat?
Date   Mon, 14 Jun 2004 16:40:17 +0200

thank you Nick, I'll try that.
Annelies

Nick Cox wrote:

> -nmissing- is a user-written command,
> last published in Stata Journal 3(4)
> 2003, so far as I can see.
>
> -tabstat- is an official Stata command.
>
> What you tried cannot be expected to
> work. The -s()- option of -tabstat- just
> accepts items from a menu indicating statistics
> to be calculated within -tabstat-. What
> you tried would only work in these
> circumstances: that if -tabstat- didn't
> recognise what you asked for, it then
> would try to find a command with the
> same name and use its results in tabulation.
> I see that this idea makes sense from your point
> of view, but it is essentially impossible to program
> without knowing what kinds of results
> would be returned by the program called, and
> arguably it is bad design in any case.
>
> However, what you want would be
> possible to program in a different way, if
> StataCorp were to extend the set of statistics
> provided to include the number of missing
> values. That would, however, require some
> restructuring of -tabstat- and arguably it
> is, again, bad design in any case, the main
> point being that -tabstat- has a clear focus
> as a wrapper for -summarize-.
>
> Loosely similar comments apply to -tabulate-
> and -table-.
>
> A cruder alternative is to cut and paste
> output from -nmissing- to go alongside
> outpot from -tabstat-. Clearly that is
> not a very attractive solution.
>
> A better alternative is to learn to
> use -tabdisp- to get what you want. In
> your example, the code might look like
>
> egen n = sum(1), by(DURSTAY DETMETH)
> egen nmissing, sum(mi(WEEKDELAY)), by(DURSTAY DETMETH)
> egen mean = mean(WEEKDELAY), by(DURSTAY DETMETH)
> tabdisp DURSTAY DETMETH , c(mean n nmissing)
>
> There is some discussion of related problems
> in
>
> Problems with tables, Part I. Stata Journal
> 3(3):309--324 (2003)
>
> Nick
> n.j.cox@durham.ac.uk
>
> A.M. Vos
>
> > I just found 'nmissing' and I hoped it was possible to use that in
> > combination with
> > tabstat, but it appeared not to. For instance, my syntax reads:
> >
> > by DURSTAY DETMETH: tabstat WEEKDELAY, s(mean n)
> >
> > and I would like to say:
> >
> > by DURSTAY DETMETH: tabstat WEEKDELAY, s( mean n nmissing)
> > that is, for each combination of durstay and detmeth
> > obtaining the mean
> > delay in
> > weeks, the number of observations on which the mean was
> > calculated, and
> > the number
> > of observations with a missing value on weekdelay.
> >
> > it would also be nice if 'nmissing' could be used in combination with
> > table and tabulate.
> > would this be possible?
>
> *
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--
A.M. Vos
dept. of Public Health
Erasmus MC
University Medical Center Rotterdam
P.O. Box 1738
3000 DR Rotterdam
The Netherlands
Tel: +31 (10) 4087502
Fax: +31 (10) 4089449
email: a.vos@erasmusmc.nl


*
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