RE: st: RE: Knowing how a variable was generated

[Ulrich Kohler <kohler@wzb.eu>]

I principal it is also possible to store this information as note: 

. sysuse auto
. gen x = weight - 1
. note x: gen x = weight - 1

. replace x = weight +1
. note x : replace x = weight + 1

. note x

Clearly it is possible to write programms (i.e. -gennote- and
-replacenote-) that do this automatically. The question however arise
why someone who is not willing to give away his do-files should use
these programs when creating a data set ...

Uli


Am Sonntag, den 31.10.2010, 17:41 +0000 schrieb Louis Boakye-Yiadom:
> That's correct. I'm looking at a situation where the do-file is not available. Indeed, often you may have to work with a dataset for which you played no role in the generation of the variables. Thanks.
> 
> Louis
> 
> 
> --- On Sun, 31/10/10, Nick Cox <n.j.cox@durham.ac.uk> wrote:
> 
> > Indeed. But Louis' question, and my
> > answers, presuppose that was not done. 
> > 
> > Nick 
> > n.j.cox@durham.ac.uk
> > 
> > 
> > Michael McCulloch
> > 
> > Wouldn't it be sufficient to simple record the work in a
> > do-file that documents the command:
> >     gen B = (A*C) + D, or
> >     gen B = A*(C + D)?
> > 
> > On Oct 31, 2010, at 9:46 AM, Nick Cox wrote:
> > 
> > > There are programs that enable users to record
> > definitions of variables as they generate or replace them.
> > See e.g. -labgen- from SSC and especially its references. 
> > > 
> > > More generally, if users employed variable labels or
> > characteristics to record the definition of variables --
> > then your problem is indeed soluble. 
> > > 
> > > I didn't imagine that's what you had in mind, as if
> > you knew that definitions were stored that way it's hard to
> > see why your question arises. 
> >  
> > Louis Boakye-Yiadom
> >  
> >  Nick, thanks for the reply. I was thinking that if it's
> > possible for Stata to store information on the generation of
> > the variable (at least in simple cases), it might be
> > possible to have this feature in Stata.
> >  
> > Nick Cox
> >  
> > >> In general, no. How could there be? 
> > >> 
> > >> However, in simple cases for Y calculated somehow
> > from X,
> > >> looking at graphs of Y vs  X might give a
> > clue. 
> >  
> > Louis Boakye-Yiadom
> >  
> > >> If some of the variables in a dataset were
> > generated by a
> > >> transformation or combination of some other
> > variable(s) in
> > >> the data, is it possible to know this without
> > seeing the
> > >> relevant log or do file? For example, consider a
> > situation
> > >> where the variables in the data include A, B, C,
> > and D, and
> > >> B was generated as follows:
> > >> B = A*C + D
> > >> Is there a command for determining how B was
> > generated?
> > 
> > *
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> > *   http://www.ats.ucla.edu/stat/stata/
> > 
> 
> 
>       
> 
> *
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