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Re: st: Creating a dummy variable under certain conditions


From   Abhimanyu Arora <abhimanyu.arora1987@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Creating a dummy variable under certain conditions
Date   Sat, 2 Jun 2012 17:21:54 +0200

Okay, if I infer correctly, try this: bys gvkey: gen
new_viol_dummy=viol+F1.viol+F2.viol+F3.viol==4.
Seems good?



On Sat, Jun 2, 2012 at 5:07 PM, sebas nicaise <sebasnicaise@hotmail.com> wrote:
> Maybe I can better show it visually:
> Your commands give me the following output:
> bys gvkey: gen new_viol_dummy=L.viol+L2.viol+L3.viol+L4.viol==0
> date    gvkey   viol    new_viol_dummy   1997q1 1004    0       01997q2 1004    0       01997q3 1004    0       01997q4 1004    0       01998q1 1004    0       11998q2 1004    0       11997q1 1021    0       01997q2 1021    0       01997q3 1021    0       01997q4 1021    0       01998q1 1021    0       11998q2 1021    0       11998q3 1021    0       11998q4 1021    1       11999q1 1021    1       01999q2 1021    1       01999q3 1021    1       01999q4 1021    0       0
> While I want this: date gvkey   viol    new_viol_dummy   1997q1 1004    0       01997q2 1004    0       01997q3 1004    0       01997q4 1004    0       01998q1 1004    0       01998q2 1004    0       01997q1 1021    0       01997q2 1021    0       01997q3 1021    0       01997q4  1021    0       01998q1        1021    0       01998q2  1021    0       01998q3        1021    0       01998q4 1021    1       11999q1 1021    1       01999q2 1021    1       01999q3 1021    1       01999q4 1021    0       0
> If it is not clear what I mean, let me know :)
> Thank you,Sebastiaan
>> Date: Sat, 2 Jun 2012 16:34:41 +0200
>> Subject: Re: st: Creating a dummy variable under certain conditions
>> From: abhimanyu.arora1987@gmail.com
>> To: statalist@hsphsun2.harvard.edu
>>
>> Sebas,
>> Adding to Nick's comment, did you not -xtset- the data? You also have
>> an option of bys id_var: command, otherwise
>>
>>
>> On Sat, Jun 2, 2012 at 4:29 PM, Nick Cox <njcoxstata@gmail.com> wrote:
>> > You will probably want to exclude or ignore the first few observations
>> > in each panel or -replace- it with missing. Otherwise, what's wrong?
>> >
>> > Abhimanyu's slip has already been corrected in this thread, as below.
>> >
>> > Nick
>> >
>> > On Sat, Jun 2, 2012 at 3:12 PM, sebas nicaise <sebasnicaise@hotmail.com> wrote:
>> >
>> >> Thank you for the quick replys.
>> >>
>> >>  However, the suggested solutions did not give the right answer.
>> >>
>> >> Nick, your solution gives me way too many 1's. I do think the first step with the cusum was the right way to go.
>> >>
>> >>  Abhimanyu, your solution does not distinquish between the id's, the calculation has to start over for every gvkey.
>> >>
>> >>
>> >>  Hope you can have another look at it, I will also try to work with the suggestions you gave me.
>> >>
>> >>> From: abhimanyu.arora1987@gmail.com
>> >>> To: statalist@hsphsun2.harvard.edu
>> >>>
>> >>> Thanks Nick, yes.
>> >>> But I would go for your solution which would be better in case he had
>> >>> a longer lag.
>> >>>
>> >>> On Sat, Jun 2, 2012 at 2:56 PM, Nick Cox <njcoxstata@gmail.com> wrote:
>> >>> > This looks OK as long as you substitute -viol- for -gvkey-. The
>> >>> > previous values concerned are for -viol-, not -gvkey-.
>> >>> >
>> >>> > Nick
>> >>> >
>> >>> > On Sat, Jun 2, 2012 at 1:51 PM, Abhimanyu Arora
>> >>> > <abhimanyu.arora1987@gmail.com> wrote:
>> >>> >
>> >>> >> Try this if your data is -xtset-ted
>> >>> >> gen new_viol_dummy=L.gvkey+L2.gvkey+L3.gvkey+L4.gvkey==0
>> >>> >
>> >>> >> On Sat, Jun 2, 2012 at 2:06 PM, sebas nicaise <sebasnicaise@hotmail.com>
>> >>> >>
>> >>> >>> I am struggeling with creating a new dummy variable. I have a very large
>> >>> >>> (unbalanced) panel dataset that looks like this:
>> >>> >>>
>> >>> >>>
>> >>> >>>
>> >>> >>> date gvkey viol
>> >>> >>> 1997q1 1021 0
>> >>> >>> 1997q2 1021 0
>> >>> >>> 1997q3 1021 0
>> >>> >>> 1997q4 1021 0
>> >>> >>> 1998q1 1021 1
>> >>> >>> 1998q2 1021 0
>> >>> >>> 1998q3 1021 0
>> >>> >>> 1998q4 1021 1
>> >>> >>> 1999q1 1021 0
>> >>> >>>
>> >>> >>> 1999q2 1021 0
>> >>> >>>
>> >>> >>> 1999q3 1021 0
>> >>> >>> 1999q2 1023 0
>> >>> >>> 1999q3 1023 1
>> >>> >>> 1999q4 1023 0
>> >>> >>> 2000q1 1023 0
>> >>> >>> 2000q2 1023 1
>> >>> >>>
>> >>> >>>
>> >>> >>> Where date is calender quarter, gvkey is the company identifier and viol a
>> >>> >>> dummy which equals 1 if the firm is in violation of a covenant in a private
>> >>> >>> debt contract.
>> >>> >>>
>> >>> >>>
>> >>> >>>
>> >>> >>> The problem is that I have to create a new dummy variable ( new violation)
>> >>> >>> which meets certain conditions.
>> >>> >>>
>> >>> >>> The new violation dummy is only allowed to be 1 if in the previous 4
>> >>> >>> quarters of a certain company (gvkey) is 0.
>> >>> >>>
>> >>> >>>
>> >>> >>>
>> >>> >>> This means for example that:
>> >>> >>>
>> >>> >>>
>> >>> >>>
>> >>> >>> date gvkey viol Newviolation
>> >>> >>> 1997q1 1021 0 0
>> >>> >>> 1997q2 1021 0 0
>> >>> >>> 1997q3 1021 0 0
>> >>> >>> 1997q4 1021 0 0
>> >>> >>> 1998q1 1021 1 1
>> >>> >>> 1998q2 1021 0 0
>> >>> >>> 1998q3 1021 0 0
>> >>> >>> 1998q4 1021 1 0
>> >>> >>> 1999q1 1021 0 0
>> >>> >>>
>> >>> >>> 1999q2 1021 0 0
>> >>> >>>
>> >>> >>> 1999q3 1021 0 0
>> >>> >>> 1999q2 1023 0 0
>> >>> >>> 1999q3 1023 1 0
>> >>> >>> 1999q4 1023 0 0
>> >>> >>> 2000q1 1023 0 0
>> >>> >>> 2000q2 1023 1 0
>> >>> >>>
>> >>> >>>
>> >>> >>>
>> >>> >>> I do not know how to tell Stata to create this variable, Hope someone is
>> >>> >>> so kind to help me.
>> >>> >
>> >>> > *
>> >>> > * 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/
>> >> *
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>> >> *   http://www.ats.ucla.edu/stat/stata/
>> >
>> > *
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>>
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>
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