RE: st: Knowing how a variable was generated

["Hoffman, George" <ghoffman@mcw.edu>]

Take a look at 'defv' (define variable) user-written command.

STB-51  dm50.1  . . . . . . . . . . . . . . . . . . . . . . . . Update to defv
        (help defv if installed)  . . . . . . . . . . . . . . .  J. R. Gleason
        9/99    p.2; STB Reprints Vol 9, pp.14--15
        updated to Stata 6 and improved

use 'findit defv' to get it over the web.

You can use it in place of generate or replace to recode a note for each variable definition step.

As an example:


. set obs 10
obs was 0, now 10

. defv x = _n

. defv x = x^x
(9 real changes made)

. defv x = _n
(9 real changes made)

. defv y = x^2

. notes

x:
  1.  generate x = _n
  2.  replace x = x^x
  3.  replace x = _n

y:
  1.  generate y = x^2

. list

     +----------+
     |  x     y |
     |----------|
  1. |  1     1 |
  2. |  2     4 |
  3. |  3     9 |
  4. |  4    16 |
  5. |  5    25 |
     |----------|
  6. |  6    36 |
  7. |  7    49 |
  8. |  8    64 |
  9. |  9    81 |
 10. | 10   100 |
     +----------+

.


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Louis Boakye-Yiadom
Sent: Tuesday, November 02, 2010 2:55 AM
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: Knowing how a variable was generated

Allan, thanks.

Louis

--- On Mon, 1/11/10, Allan Reese (Cefas) <allan.reese@cefas.co.uk> wrote:

> From: Allan Reese (Cefas) <allan.reese@cefas.co.uk>
> Subject: Re: st: Knowing how a variable was generated
> To: statalist@hsphsun2.harvard.edu
> Date: Monday, 1 November, 2010, 17:25
> "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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