The short answer is, again: Because one is documented, and the other
isn't.
It really doesn't matter which one you use, as they are identical in
terms of definition and results. In your case, as a long-time Stata
user,
it is quite possible that you are aware of both, or use programs or do
files that separately use -egen, sum()- and -egen, total()-, but none of
that matters, unless StataCorp has confused you by its syntax change.
The main issue I see as this. If -egen, sum()- is mentioned, then anyone
who is using Stata 9 or Stata 10 will not find that documented. -egen,
sum()- means nothing to anyone except users of Stata 8 down and people
with long memories. The people with long memories don't need this
explanation. We have a convention that Statalist takes the current
version as standard: manifestly that does not rule out explanations like
this one.
As often reported, Statalist stalwart Svend Juul was the stimulus for
this name change. He pointed out that the function -sum()- means and has
long meant cumulative (running) sum, so the -egen, sum()- function was
out-of-line and the one to give way. It was renamed -egen, total()- in
Stata 9.
I can see a case for documenting old names as well as new, but the
cost-benefit analysis does not seem clear-cut to me. Where does one draw
the line, for example? Perhaps there are users who can remember that the
-log- command had a different name in Stata 1.0.
Nick
[email protected]
Feiveson, Alan H.
So how I would know to use "total" instead of "sum"? Is there a
searchable list of commands and options that have essentially the same
function in different versions of Stata, but with different names? In
this example, I would like to specify "-egen, sum() and this magic list
would come back with something like what you said below. (Ha)
Nick Cox
-egen, total()- is documented as of Stata 9 up.
-egen, sum()- is not. No other difference. So the former, -total()-, is
now recommended for all users of Stata 9 up.
Johannes Geyer
Nick: What is the difference between -total()- and -sum()- that makes
the latter better than the other?
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