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st: Calculating span exculsive of the current spell
From
Kai Huang <[email protected]>
To
"[email protected]" <[email protected]>
Subject
st: Calculating span exculsive of the current spell
Date
Mon, 10 Jun 2013 12:50:19 +0000
Dear all,
I have a spell dataset as follows:
ID Start End X
433 1987 1990 1
433 1990 1992 1
433 1992 1994 2
433 1994 1997 1
433 1997 2000 3
433 2000 2004 2
433 2004 2006 3
where x is a dummy indicating activity status. I have the following commands for calculating the span of the respondent in each status:
gen span=End-Start
by ID: gen span1=sum(span) if X==1
by ID: gen span2=sum(span) if X==2
by ID: gen span3=sum(span) if X==2
drop duration
3 new variables are added to the dataset:
ID Start End X span1 span2 span3
433 1987 1990 1 3 . .
433 1990 1992 1 5 . .
433 1992 1994 2 . 2 .
433 1994 1997 1 7 . .
433 1997 2000 3 . . 3
433 2000 2004 2 . 6 .
433 2004 2006 3 . . 5
The above commands calculate the span including the current spell. I would like to know how can we calculate the span excluding the current spell so that we have the following values instead:
ID Start End X span1 span2 span3
433 1987 1990 1 0 . .
433 1990 1992 1 3 . .
433 1992 1994 2 . 0 .
433 1994 1997 1 5 . .
433 1997 2000 3 . . 0
433 2000 2004 2 . 2 .
433 2004 2006 3 . . 3
Thank you very much in advance.
Best regards,
Kai Huang
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