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Re: st: Counting firms in a panel dataset
From
Nick Cox <[email protected]>
To
"[email protected]" <[email protected]>
Subject
Re: st: Counting firms in a panel dataset
Date
Thu, 16 Jan 2014 11:30:38 +0000
Sorry, but I am lost here. Clearly I don't have your data and you
don't even show your code, nor do I understand in what sense what any
code used doesn't work.
As I understand it, you want to identify the 11 observations that
appear when 408 are selected but do not appear when 397 are selected.
I am waving general logic at you, namely that
the complement of A & B in A is A & !B
and you don't identify a fallacy in that.
What are you showing us? It's not 11 observations.
Nick
[email protected]
On 16 January 2014 11:10, Miguel A. Duran <[email protected]> wrote:
> Yes, Nick, I tried something quite similar, and I have just tried what you
> propose. If I am not mistaken the reason why it doesn't work is because
> -!(var1 == 10/var2 | var1 == 11/var2)- includes observations 1, 2 and 4 for
> id1 and all observations of id2. Therefore, both agents are taken into
> account under -codebook id if...-
>
> obs id startdate date var1 var2 mean_var1
> 1 1 189 187 10 .
> 10.75
> 2 1 189 188 11 .
> 10.75
> 3 1 189 189 11 1 10.75
> 4 1 189 190 11 .
> 10.75
> 5 2 192 189 10 .
> 10.5
> 6 2 192 190 10 .
> 10.5
> 7 2 192 191 11 .
> 10.5
> 8 2 192 193 11 .
> 10.5
>
> -----Mensaje original-----
> De: [email protected]
> [mailto:[email protected]] En nombre de Nick Cox
> Enviado el: jueves, 16 de enero de 2014 11:51
> Para: [email protected]
> Asunto: Re: st: Counting firms in a panel dataset
>
> Did you try it? As I understand it, the complement of
>
> A & B
>
> in A is
>
> A & !B
>
> Nick
> [email protected]
>
>
> On 16 January 2014 10:36, Miguel A. Duran <[email protected]> wrote:
>> Thanks, Nick, for your answer. I thought of something similar to what
>> you propose, but if I am not mistaken it has a problem: I would be
>> counting both
>> id1 and id2, i.e., I would get again 408 (what I get just using
>> -codebook id if mean_var1 != 11-).
>>
>> id startdate date var1 var2 mean_var1
>> 1 189 187 10 . 10.75
>> 1 189 188 11 . 10.75
>> 1 189 189 11 1 10.75
>> 1 189 190 11 . 10.75
>> 2 192 189 10 . 10.5
>> 2 192 190 10 . 10.5
>> 2 192 191 11 . 10.5
>> 2 192 193 11 . 10.5
>>
>> -----Mensaje original-----
>> De: [email protected]
>> [mailto:[email protected]] En nombre de Nick Cox
>> Enviado el: miércoles, 15 de enero de 2014 20:28
>> Para: [email protected]
>> Asunto: Re: st: Counting firms in a panel dataset
>>
>> I'd look at data that satisfy
>>
>> if mean_var1 != 11 & !(var1 == 10/var2 | var1 == 11/var2)
>>
>> i.e. negating the second condition. Note that if -var1- and -var2- are
>> both missing, then the second condition
>>
>> (var1 == 10/var2 | var1 == 11/var2)
>>
>> reduces to
>>
>> . == .
>>
>> which is always true.
>> Nick
>> [email protected]
>>
>>
>> On 15 January 2014 19:18, Miguel A. Duran <[email protected]> wrote:
>>> Hi, Statlisters. I am using -codebook- to count the number of agents
>>> in a panel dataset under different criteria. Under a criterion I get
>>> 408 agents and under another one I get 397. I have an intuition about
>>> the cause of this difference and I would like to check it out, but I
>>> do
>> not know how to do it.
>>> To help make clear my point, (the relevant part of) my dataset looks
>>> similar to this,
>>>
>>> id startdate date var1 var2 mean_var1
>>> 1 189 187 10 . 10.75
>>> 1 189 188 11 . 10.75
>>> 1 189 189 11 1 10.75
>>> 1 189 190 11 . 10.75
>>> 2 192 189 10 . 10.5
>>> 2 192 190 10 . 10.5
>>> 2 192 191 11 . 10.5
>>> 2 192 193 11 . 10.5
>>>
>>> Using the command -codebook id if mean_var1 != 11- I get 408 agents,
>>> but using the command -codebook id if mean_var1 != 11 & (var1 ==
>>> 10/var2 | var1 == 11/var2)- I get 397 agents. My intuition is that
>>> this happens because there are agents (like agent 2) that do not have
>>> the observation corresponding to the startdate. If I am right adding
>>> this requirement to the command -codebook id if mean_var1 != 11-
>>> should count 11 agents, but I do not know how to include that
> requirement.
>> Will anyone please help with this?
>>> Thanks in advance.
>>>
>>> Miguel.
>>>
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