Sorry. I didn't mention that I do not have comprehensive data on the point
of time when the companies were delisted / taken off the market.
So basically I have to assume that if the values repeat up to present time,
that the point where the value is repeated the first time and afterwards
does not change anymore is the point of the delisting.
- Tom
-----Urspr�ngliche Nachricht-----
Von: [email protected]
[mailto:[email protected]] Im Auftrag von Nick Cox
Gesendet: Donnerstag, 7. Dezember 2006 18:45
An: [email protected]
Betreff: st: RE: Repeating values
I don't understand the match between your problem
and your solution.
Sounds to me like
replace var1 = . if status == "Delisted"
but I'm quite likely misunderstanding.
Nick
[email protected]
Thomas Erdmann
> I am working with some variables that or "wrong" in the sense
> that if one
> share was taken off the market (i.e. the company was
> dissolved), the last
> value of the variable is repeated instead of containing
> missing values.
>
> e.g.
>
> Status Year Var1
> Listed 1991 0.9
> Listed 1992 0.95
> Listed 1993 0.93
> Delisted 1994 0.93
> Delisted 1995 0.93
> ..
> Delisted 2006 0.93 (value is always repeated up to present time)
>
> Whereas years 1994-2006 should contain missing values. I came
> up with this
> cleaning process:
>
> foreach X of varlist var1 var2 var3 {
> generate `X'new=`X'
> replace `X'new=. if `X'==L.`X'
> replace `X'=`X'new
> drop `X'new
> }
>
> Which is okay, but also sets the value to missing if one
> observation for a
> listed company repeats, so it also deletes observations that
> would be fine.
>
> Any suggestions on how I can only replace the "wrong" values?
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