Re: st: Knowing how a variable was generated

["Allan Reese (Cefas)" <allan.reese@cefas.co.uk>]

"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?"

It would be possible for software to record "created" and "last
modified" dates for each variable, but it doesn't.  It seems rather
onerous to record the complete history: a variable might be generated,
subsequently recoded or specified values replaced (with if or in), or
edited as individual values (each of which creates a replace for that
unit.  It is unsafe to rely on the user having recorded all actions in
the label.

That is why I have advocated having a profile.do that creates a daily
log file so that all user commands are captured, including those created
by edits. I have hundreds of text files logYYYY-MM-DD.txt. 

* Sprinkle with comments as it is otherwise hard, weeks later, to work
out *why* you wrote specific commands, and of course the log contains
all mistakes and blind alleys as well as the yellow brick road to
happiness.

I regularly remind myself how variables came about by searching the logs
for variable or file names.  The one operation that creates no log is
pasting data from an arbitrary range of an Excel spreadsheet. That needs
a comment, then wash you hands.  

Allan 


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