# RE: st: Re: How to detect the change of i over t?

 From Benson Limann To stata , Subject RE: st: Re: How to detect the change of i over t? Date Mon, 9 Feb 2009 14:29:27 -0700

```Hi Martin: many thanks! Ben

----------------------------------------
> From: martin.weiss1@gmx.de
> To: statalist@hsphsun2.harvard.edu
> Subject: st: Re: How to detect the change of i over t?
> Date: Sun, 8 Feb 2009 10:52:24 +0100
>
> <>
>
> See NJC`s FAQ: http://www.stata.com/support/faqs/data/panel.html
>
> *********
> clear*
> set obs 20
> egen float id = seq(), from(1) to(4) block(5)
> egen float t = seq(), from(1) to(5) block(1)
> g x=cond(runiform()<=0.5,0,1)
> g byte become=.
> bys id: replace become=cond(x[_n-1]==0 & x[_n]==1,1,0)
> list, noo sepby(id)
> ***********
>
> HTH
> Martin
> _______________________
> ----- Original Message -----
> From: "Benson Limann"
> To: "stata"
> Sent: Sunday, February 08, 2009 5:46 AM
> Subject: st: How to detect the change of i over t?
>
>
>> Hi all:
>>
>> I am using an unbalanced panel dataset. i is ID and t is time. Every (i,t)
>> has a characteristic x=0 or 1.
>>
>> I want to generate a variable called "become" such that for each (i,t):
>>
>> become=1, if x=0 at time t-1, and x=1 at time t
>> become=0, otherwise
>>
>> How to write it? My primary concern is how to deal with the first t for
>> each i--this observation does not have t-1.
>>
>> Any suggestion would be greatly appreciated.
>>
>> Ben
>>
>>
>> _________________________________________________________________
>> Windows Live™: E-mail. Chat. Share. Get more ways to connect.
>> http://windowslive.com/howitworks?ocid=TXT_TAGLM_WL_t2_allup_howitworks_022009
>> *
>> * 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/
>>
>
> *
> * 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/
_________________________________________________________________
Windows Live™: Keep your life in sync.
http://windowslive.com/explore?ocid=TXT_TAGLM_WL_t1_allup_explore_022009
*
*   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/
```