Re: st: RE: a variable is decreased by 1 ? Thanks

[Gijs Dekkers <gd@plan.be>]

Dear Kris, dear Nick,

Thanks for the help. Before posting this request, I did try setting the 
variable type to 'long' but that did not resolve the problem. However, 
Kris' suggestion is spot on! So, thanks Kris for the immediate solution. 
And thanks Nick, for the explanation which I am going to study now to 
prevent these kinds of problems in the future.

Gijs


De Swerdt, Kris wrote:


> Gijs,
>
> Is it possible that the variable pid is of storage type double and pidold of storage type float?
> Maybe you can try:
> 	gen double pidold=pid
>
> Kris
>
> -----Original Message-----
> From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Gijs Dekkers
> Sent: maandag 8 januari 2007 14:06
> To: statalist@hsphsun2.harvard.edu
> Subject: st: a variable is decreased by 1 ?
>
> Dear fellow Stata-users,
>
> I really would appreciate some help with this strange problem...
>
> I have a panel dataset, with the individual number 'pid' and the year 
> variabele 'jaar'. The variable pidnew is an alternative 
> individual-identification number. This variabel, and 'jaar' don't really 
> do anything, but I include it to show that the individual does not 
> changes in what follows.
>
> So, the starting dataset is:
>
> . list pid pidnew jaar if (pid==17025101 & jaar==2002)
>
>            +--------------------------+
>             |      pid       pidnew   jaar  |
>             |--------------------------|
> 10597. | 17025101       62   2002 |
>            +--------------------------+
>
> So this is the data line of individual 17025101 in the year 2002. Now I 
> create a copy ('pidold') of this individual identification number,
>
> . gen pidold = pid
>
> . list pid pidold pidnew jaar if (pid==17025101 & jaar==2002)
>
>            +-------------------------------------+
>             |      pid         pidold       pidnew   jaar |
>             |-------------------------------------|
> 10502. | 17025101   1.70e+07       62   2002 |
>            +-------------------------------------+
>
> The resulting variable is difficult to read, for it is in the scientific 
> notation. So I change the format...
>
> . format pid pidold epid %14.0f 
> . list pid pidold pidnew jaar if (pid==17025101 & jaar==2002)
>
>            +-------------------------------------+
>            |      pid         pidold           pidnew   jaar |
>            |-------------------------------------|
> 10597. | 17025101   17025100       62   2002 |
>            +-------------------------------------+
>
> And all of a sudden, the variabele 'pidold', which is supposed to be 
> equal to 'pid' has decreased by one! Or, which is more likely, the 'gen 
> pidold = pid' has not done what it should have done, because the format 
> of pidold was set so that information was lost. However, I cannot set a 
> format of a variable prior to its existence.
>
> I have also tried juggling with 'recast' and different formats, but 
> nothing seems to help.
>
> I would really appreciate your help in finding a solution!
>
> Gijs
>
>
>
>
>
>
>
>  

--
Gijs Dekkers
Attach� Federal Planning Bureau
Research fellow CESO, Katholieke Universiteit Leuven
Kunstlaan 47-49 Avenue des Arts
1000 Brussels, Belgium
phone ++32/(0)2/5077413
fax  7373
skype gdekkers2209
gd@plan.be, gijs.dekkers@soc.kuleuven.be



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