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RE: st: Creating a dummy variable under certain conditions


From   sebas nicaise <sebasnicaise@hotmail.com>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: Creating a dummy variable under certain conditions
Date   Sun, 3 Jun 2012 17:46:08 +0000

Dear Abhimanyu,

This also does not give me the right answer.It gives:

date    gvkey   viol    new_viol_dummy1998q4    1095    0     01999q1 1095    0     01999q2 1095    0     01999q3 1095    0     01999q4 1095    1     02000q1 1095    0     02000q2 1095    1     12000q3 1095    1     12000q4 1095    1     12001q1 1095    1     12001q2 1095    1     12001q3 1095    1     0

It should be:000010000000

I think the command should be more complicated since the new viol dummy variable is only 1 under certain strict conditions.NEWVIOL is only 1 if the VIOL dummy of the corresponding GVKEY has a 1 IF in the four previous quarters a 0. Furthermore, if NEWVIOL documents a 1, it can only be a 1 again after four quarters of 0.

Hope you, or someone else, can help me with this seemingly easy task :)

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