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

[Nick Cox <n.j.cox@durham.ac.uk>]

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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