RE: st: RE: -finddup- for panel?

["joe J." <otharain@hotmail.com>]

Thanks Nick.

Here is what I meant.

Panel variable: id, time variable: year

There is a variable y which has missing values and I want to use -cipolate- 
--the stata-code available at SSC--to interpolate the missing values. I do 
the interpolation the following way.

tsset id year, yearly
by id : cipolate y   year, gen(yci)

It does not run because id has some duplicates, which resulted due to 
data-entry errors. Therefore I want to remove duplicates for each year and 
do -cipolate- (the cubic interpolation code at ssc) on the resulting data 
set with unique ids.

I remove duplicates the following way for each year.

use "C:\data75.dta", clear
finddup id if year==1975, nol k/*finddup is also downloadable from ssc*/
save "C:\data75a.dta", replace

drop if dupval>=2/*removing duplicates*/
save "C:\data75b.dta", replace/*data with unique ids*/

by id : cipolate y   year, gen(yci)/*cubic interpolation*/
save "C:\data75c.dta", replace


use "C:\data75a.dta", clear
keep if dupval>=2/*collecting duplicates*/
save "C:\data75d.dta", replace

I repeat the above steps for other years and at the end append the 
interpolated and duplicate files for each year.

use "C:\data75c.dta", clear
append using "C:\data75d.dta"
append using "C:\data76c.dta"
append using "C:\data76d.dta"
etc.
My question is , is there any way of detecting duplicate ids for all years 
simaltaneosly instead of doing it for each year sepearately. (I wish I could 
do it the following way
by year: finddup id , nol k).

Joe


> From: "Nick Cox" <n.j.cox@durham.ac.uk>
> Reply-To: statalist@hsphsun2.harvard.edu
> To: <statalist@hsphsun2.harvard.edu>
> Subject: st: RE: -finddup- for panel?
> Date: Tue, 20 Apr 2004 17:32:05 +0100
>
> Please show us an example of what you mean.
>
> Nick
> n.j.cox@durham.ac.uk
>
> > -----Original Message-----
> > From: owner-statalist@hsphsun2.harvard.edu
> > [mailto:owner-statalist@hsphsun2.harvard.edu]On Behalf Of joe J.
> > Sent: 20 April 2004 17:22
> > To: statalist@hsphsun2.harvard.edu
> > Subject: st: -finddup- for panel?
> >
> >
> > Hello,
> >
> > I have a panel data set, where there are duplicates of the
> > panel variable.
> > But I want to retain them because the mistake is only in the
> > panel variable,
> > not in other variables in the observation. (For my analysis, I would
> > aggregate the data so that the panel variable is no longer relevant.)
> >
> > BUT, I keep the panel format in the beginning in order to
> > fill in missing
> > values using interpolation. To do this I want to keep out
> > observations with
> > the duplicate panel variable and append them back after
> > interpolation has
> > been done. For a non-panel data, I could use the stata-code
> > -FINDDUP- (by
> > Fred Wolfe downloadable from SSC). -finddup- helps to take
> > out a particular
> > duplicate observation and save it for later use. But it does
> > not work in a
> > panel set up. Is there any way around, other than doing it
> > sepeartely for
> > each year?
>
> *
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