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Re: st: Creating a dummy variable under certain conditions


From   Nick Cox <njcoxstata@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Creating a dummy variable under certain conditions
Date   Mon, 4 Jun 2012 11:06:37 +0100

Quite so. Let's try something different.

gen history = ""
bysort gvkey (date) : replace history = string(viol) + history[_n-1]
gen OK = substr(history, 1, 5) == "10000"

Nick

On Mon, Jun 4, 2012 at 10:38 AM, sebas nicaise <sebasnicaise@hotmail.com> wrote:
>
> Nick your code is almost right. Only it gives a 1 for these cases while it should not:
>
> date gvkey viol myindicator
> 2000q3 1045 0 0
> 2000q4 1045 0 0
> 2001q1 1045 0 0
> 2001q2 1045 0 0
> 2001q3 1045 1 1
> 2001q4 1045 1 0
> 2002q1 1045 0 0
> 2002q2 1045 0 0
> 2002q3 1045 0 0
> 2002q4 1045 1 1
> 2003q1 1045 1 0
> 2003q2 1045 0 0
>
> You see, because viol is 1 again after the new viol reported a 1. So it is wrong because there are only 3 quarters of 0 in the viol dummy.
>
>
> Abrihmanyu, in your code it gives to few 1's But if it reports a 1 it is right. I do not see the error in the code...
>
>
>
>
> ----------------------------------------
>> Date: Mon, 4 Jun 2012 09:41:24 +0100
>> Subject: Re: st: Creating a dummy variable under certain conditions
>> From: njcoxstata@gmail.com
>> To: statalist@hsphsun2.harvard.edu
>>
>> bysort gvkey (date) : gen cuviol = sum(viol)
>> by gvkey : gen myindicator = (viol == 1) & (cuviol[_n-1] ==
>> cuviol[_n-4]) & _n> 4
>>
>> Nick
>>
>> On Mon, Jun 4, 2012 at 9:22 AM, sebas nicaise <sebasnicaise@hotmail.com> wrote:
>>
>>> It is important that new viol dummy can only be 1 if viol is 1 and in the previous 4 quarters viol is 0.
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