> "Riano, Alejandro" wrote:
>
> > I'm collapsing the standard deviation for a set of
> variables (monthly
> > frequency):
> >
> > collapse (sd) er rer, by(country_name year)
> >
> > but if for example one country doesn't have data for all
> the year, i'm
> > getting a 0 instead of a missing value after doing the
> collapse, do you know
> > how can i solve this ?
This was fixed in the Stata update of 02 August 2002, as discussed in
this clip from -help whatsnew-. Type "update query" and follow the
directions to update.
----- update 02aug2002 ------------------------
1. collapse would generate 0 for the standard deviation (sd) of a
variable that equaled missing value (.) in all observations even though
it would generate missing value for the mean. collapse now generates
missing value for the standard deviation, too.
-Nick Winter
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