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st: generate new variable from differencing where subtracted variable is fixed
From
Johannes Schoder <[email protected]>
To
[email protected]
Subject
st: generate new variable from differencing where subtracted variable is fixed
Date
Fri, 05 Mar 2010 17:00:06 +0100
Dear Statalist users:
I try to calculate the difference between two variables for a panel data
set, where the subtracted variable (here x2) is always the first
observation of each year:
For example:
Year x1 x2 difference: x1-x2 if x2 is the first obs. of the year
1960 5 8 5-8
1960 4 10 4-8
1960 2 3 2-8
1961 5 7 5-7
1961 1 2 1-7
1961 3 5 3-7
I tried something like: bysort year: gen difference= x1-x2[_n==1] but
Stata does only calculate the first observation for each year and
otherwise generates missings.
Thanks a lot for any hint!
Regards,
Johannes
--
Johannes Schoder
Socioeconomic Institute
University of Zurich
Hottingerstr. 10
8032 Zurich
Phone: +41 44 634 0612
Fax: +41 44 634 4987
E-mail: [email protected]
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