Dana:
I'm not sure that I completely understand how your data is structured,
but I would use -tabout- to get at your main question--that of easily
creating an excel table of the average % changes in some variable
between a year and a base year (or before & after some year).
I like to work with this kind of data in wide, rather than long,
format, but you could adapt this same use of -tabout- to your data in
long format.
**********************
clear
local sf `"`pwd'"'
input year var
1990 3
1991 4
1992 5
1990 7
1991 15
1992 3.2
1990 9
1992 3
end
//SET-UP
gen id = [_n]
reshape wide var, i(id) j(year)
**
rename var1990 base_var1990
replace base_var1990 = base_var1990[_n-1] /*
*/ if base_var1990==.
foreach v in 1991 1992 {
gen pctdiff_var`v' = (var`v'/base_var1990)
label var pctdiff_var`v' "Percent Change from `v' and 1990"
}
//TABOUT EXAMPLE
tabout base_var1990 using "`sf'/test.xls", /*
*/ c(mean pctdiff_var1991 mean pctdiff_var1992) /*
*/ replace h1(TABLE Title) lines(double) f(2p) sum
**********************
Best,
Eric
__
Eric A. Booth
Public Policy Research Institute
Texas A&M University
[email protected]
Office: +979.845.6754
On Aug 27, 2009, at 7:32 PM, Dana Chandler wrote:
Is there any module or easy way to calculate percentage changes in
stata? That is to say, a percentage change relative to some base
period. I am interested in an easy way to make a summary table of
percent changes to have exported to either excel or powerpoint.
Currently, supposing that my data has a "before" and "after"
observation in long form and then any number of other potential
categories, I either do a bunch of egens to create the totals and then
calculate the percent changes. Next, I "tag" whatever the unit of
observation is and then I make a table showing the mean of the percent
change. Alternatively, I could create and export a table that shows
the before and afters and then put that in excel and then calculate %
changes. Both processes seem really tedious.
Is there any easy way to do this in Stata?
Thanks in advance,
Dana
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