SV: st: calculating differences in variables in Longitudinal Data

[Alexander Zoran Dozet <zod_63@yahoo.se>]

Great! Thank you for your the speddy help!
However I run into some difficulties when some of the values are missing for some observations. 

I get the error message:


"nothing found where name expected"
r(198);


Is there any way to handle that?

Again, thank you!

Best regards
Alexander Dozet




----- Ursprungligt meddelande ----
Från: Abhimanyu Arora <abhimanyu.arora1987@gmail.com>
Till: statalist@hsphsun2.harvard.edu
Kopia: 
Skickat: måndag, 9 april 2012 21:36
Ämne: Re: st: calculating differences in variables in Longitudinal Data

Hi

I would do it as follows

tsset year
forvalues i=1/54{
gen diff`i'=.
bys company:replace diff`i'=S2.var`i' if year==2011
}

Cheers
Abhimanyu

On Mon, Apr 9, 2012 at 9:23 PM, Alexander Zoran Dozet <zod_63@yahoo.se> wrote:
>
> Dear Statausers,
>
> I have a small problem
> that I suppose is easy to resolve if one knows the ansewer. Although it
> probably is basic, I have tried to solve it by searching the internet
> and hitting the books, I have not succeded in finding an answer.
>
> I have a dataset that looks like this:
>
>
> Company                Year                    Variable1                Variable2                Variable3.........Variable54
>
> Company1              2009                    60                            70                           80
> Company1              2010                    65                            72                           81
>
> Company1              2011                    67                            71                           85
>
> Company2              2009                    85                            80                           70
>
> Company2              2010                    75                            85                           78
>
> Company2              2011                    77                            88                           76
>
> .
> .
> .
> Company154
>
>
> I hope the displayed data structure is kept in this e-mail.
> Each company is occuring one time each year for each variable in the data
> set (panel data). My variable Company is in string form. I have not
> declared my dataset to be panel data. String is not allowed as an
> identifier.
>
> I want to examine the difference between the
> year 2010 and 2011 for each company and for each variable and to create a new variable for each of the differences for
> example diffVar1, diffVar2,....
>
> I would be much grateful for any help!
>
> Best regards and cheers
> Alexander Dozet
>
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