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RE: st: How to generate dummy for the following years


From   umut senalp <uerksan@hotmail.com>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: How to generate dummy for the following years
Date   Fri, 27 Jul 2012 13:14:53 +0300

Dear Ronnie,

Thank you for your reply, as you said, the code you provided has generated "always_exporter" successfully.  

Regarding to your latest reply: 

generate starter == .
replace starter == 1 if export2003 == 0 & export2004 == 1 

I do not think that I will be able to capture all "starters" with this way practically, since some firms start to export 2005 some of them 2007 etc. So I need to write a code to find the first export dummy taking the value of "1" for each firm, it will show me that the firm switch from 0 to 1 first time (means it start to export). I tried to show what I am trying to do with an example below. Thanks again,

Best

Umut
firm id    year export  starter
> 1        2003    0       0
> 1        2004    0       0       
> 1        2005    0       0
> 1        2006    1       1
> 1        2007    0       0
> 1        2008    1         0
> 1        2009    1       0
> 1        2010    1       0
> 1        2011    1       0
> 2        2003    0       0
> 2        2004    0       0
> 2        2005    0       0
> 2        2006    0       0
> 2        2007    1       1
> 2        2008    0       0
> 2        2009    0       0
> 2        2010    0       0
> 3        2003    0       0 
> 3        2004    1       1
> 3        2005    1       0 
> 3        2006    0       0
> 3        2007    0       0
> 3        2008    0       0
> 3        2009    0       0 
> 3        2010    0       0
> 3        2011    1       0 
> 4        2010    0       0
> 4        2011    1       1 


----------------------------------------
> Date: Fri, 27 Jul 2012 08:42:03 +0300
> From: rb.glists@gmail.com
> To: statalist@hsphsun2.harvard.edu
> Subject: Re: st: How to generate dummy for the following years
>
> Umut
> Reading through your email again, I don't think I answered your question so the only useful part of my earlier response may be how to generate always_exporter.
>
> Ps: For what you were trying to do with
>
> **
> gen starter=0
> replace starter=1 if export==0 in 2003 & export==1 in 2004
>
> ***
>
> I am wondering if what you are looking for is a -reshape-, so
>
> reshape wide export, i(firm_id) j(year)
>
> This would give you
>
> firm_id export2003 export2004 export2005 export2006 export2007 export2008 export2009 export2010 export2011
> 00028073 1 1 0 1 0 1 1 1 1
> 00036721 0 0 0 0 0 0 0 0 .
> 00047152 1 1 1 0 0 0 0 0 1
> 00063351 . . . . . . . 1 1
> 00144277 . . . . 1 1 0 1 .
> 00144614 . . . . . . 0 0 .
> 00145362 1 1 1 . . . . . .
> 00147034 1 1 1 1 1 1 1 1 .
>
> You can then
> generate starter == .
> replace starter == 1 if export2003 == 0 & export2004 == 1
>
> Or, to create a dummy, you can
> gen starter = export2003 == 0 & export2004 == 1
>
> Ronnie
> --
>
>
> 010100100110111101101110011011100110100101100101
>
>
>
>
> On Friday, July 27, 2012 at 12:28 AM, Ronnie Babigumira wrote:
>
> > Umut,
> > Regarding your original question on generating dummies. There will be more direct ways but here is one way to do it.
> >
> > clear
> > input str8 firm_id year export
> > 00028073 2003 1
> > 00028073 2004 1
> > 00028073 2005 0
> > 00028073 2006 1
> > 00028073 2007 0
> > 00028073 2008 1
> > 00028073 2009 1
> > 00028073 2010 1
> > 00028073 2011 1
> > 00036721 2003 0
> > 00036721 2004 0
> > 00036721 2005 0
> > 00036721 2006 0
> > 00036721 2007 0
> > 00036721 2008 0
> > 00036721 2009 0
> > 00036721 2010 0
> > 00047152 2003 1
> > 00047152 2004 1
> > 00047152 2005 1
> > 00047152 2006 0
> > 00047152 2007 0
> > 00047152 2008 0
> > 00047152 2009 0
> > 00047152 2010 0
> > 00047152 2011 1
> > 00063351 2010 1
> > 00063351 2011 1
> > 00144277 2007 1
> > 00144277 2008 1
> > 00144277 2009 0
> > 00144277 2010 1
> > 00144614 2009 0
> > 00144614 2010 0
> > 00145362 2003 1
> > 00145362 2004 1
> > 00145362 2005 1
> > 00147034 2003 1
> > 00147034 2004 1
> > 00147034 2005 1
> > 00147034 2006 1
> > 00147034 2007 1
> > 00147034 2008 1
> > 00147034 2009 1
> > 00147034 2010 1
> > end
> >
> > * Always exporter
> > tempvar foo
> > bys firm_id : egen `foo' = mean(export)
> > gen always_exporter = `foo' == 1
> >
> > * Start and end data for exporters
> > * Split data
> > tempfile fdata nedata
> > save `fdata'
> > drop if export == 1
> > save `nedata'
> > use `fdata'
> > keep if export == 1
> >
> > bysort firm_id (year): gen start= year[1]
> > bysort firm_id (year): gen end= year[_N]
> >
> > * Append non-export data and fillin missing data
> > append using `nedata'
> > bys firm_id (start): replace start = start[_n-1] if start >= .
> > bys firm_id (end): replace end = end[_n-1] if end >= .
> >
> > sort firm_id year
> > list, sepby(firm_id)
> >
> >
> >
> > Hope this is helpful
> >
> > Ronnie
> >
> > --
> > 010100100110111101101110011011100110100101100101
> >
> >
> >
> >
> > On Thursday, July 26, 2012 at 6:07 PM, umut senalp wrote:
> >
> > > Dear Stata Listers,
> > >
> > > I am using StataSE 12. I have an unbalanced data for over 2000 firms (covering the period 2003-2011) and I have a dummy variable for the firms' export status (Export=1 if firm have positive export value that year). While, a few firms observed for all 9 years (2003-2011), majority of them observed for minimum 2 years consecutively.
> > > I want to create a new set of dummy variables indicating the year that a firm started to export (Starter),
> > > one year before starting to export (Year_before),and for the following two years that the firm started to export which are Year_After and Two_Years_After.
> > > So, I want to generate 4 new dummies based on the firm's Export status. In addition to that, I have some firms which are exporter for the all period that they are observable (means I do not know when they started to export), and I want to name them as Always_Exporter.
> > >
> > > Since I am not so familiar with programming in Stata I tried following command but it failed, it was just for the firms that I have observation for 2003 onwards, anyway.
> > > gen starter=0
> > > replace starter=1 if export==0 in 2003 & export==1 in 2004
> > >
> > > And I realised that this approach will not work since I need to do it for many times for following years to catch all starters.
> > >
> > > Well, I think I need to use a program that includes loop but I don't know where to start to write the code. I would be glad if you could help me on this issue. I hope I've the issue clear enough.
> > >
> > > Kind regards
> > >
> > > Umut SENALP
> > > *
> > > * For searches and help try:
> > > * http://www.stata.com/help.cgi?search
> > > * http://www.stata.com/support/statalist/faq
> > > * http://www.ats.ucla.edu/stat/stata/
> >
>
>
>
> *
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> * http://www.ats.ucla.edu/stat/stata/
 		 	   		  
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