<>
Using Nick Cox's -egenmore- package (SSC):
/* Spells */
clear*
// ssc install egenmore, replace
input forecast_no analystID employerID
1 1 1
2 1 1
3 1 1
1 2 1
2 2 1
3 2 2
4 2 2
1 3 3
2 3 4
end
egen nvalsID = nvals(employerID), by(analystID)
drop if nvalsID==1
list, clean
/* end */
T
On Wed, Jun 10, 2009 at 11:39 PM, Howard Lempel<[email protected]> wrote:
> Not sure if this is the most efficient way, but:
>
> ******* Begin example ********
> /*
> Create a variable with the mean absolute deviation from the mean of employer ID for each analyst. This will be 0 if the employer ID never changes.
> */
> by analystID: egen Demp = mdev(employerID)
>
> // Drop observations where the employer ID never changed.
> drop if Demp==0
> ****** End Example **********
>
> Hope this helps.
> Howie
>
> Howie Lempel
> Research Assistant
> The Brookings Institution | Economic Studies
>
> 1775 Massachusetts Ave NW | Washington DC 20036
> [email protected] | p: (202) 238-3576
>
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf Of Stefano Bonini
> Sent: Wednesday, June 10, 2009 6:18 PM
> To: [email protected]
> Subject: st: dropping observation
>
> Hi
> I have a huge panel dataset containing analyst forecasts. Each analyst is associated with an employer. Sometimes analyst change employer. I want to restrict my dataset, dropping the observations of analysts that never change employer. The dataset may look like this
>
> forecast# analystID employer ID
> 1 1 1
> 2 1 1
> 3 1 1
>
> 1 2 1
> 2 2 1
> 3 2 2
> 4 2 2
>
> 1 3 3
> 2 3 4
>
> In this case I'd nee to drop all observations by analyst 1 because he never changes employer, while keeping those of analysts 2 and 3.
>
> I really cannot figure out the way to do it as visual inspection is just impossible with over 1.2m obs.
>
> Thanks!
>
> Stefano
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recursive class signs r, such that neither v Gen r nor Neg(v Gen r)
belongs to Flg(κ) (where v is the free variable of r).
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