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RE: st: Counting firms in a panel dataset
From
"Miguel A. Duran" <[email protected]>
To
<[email protected]>
Subject
RE: st: Counting firms in a panel dataset
Date
Thu, 16 Jan 2014 13:10:02 +0100
Nick, thanks for your help. I will try to be clearer. There is no fallacy in
your logic argument, but this is not the problem. In addition, what I am
showing is a simplified version of the relevant part of my dataset (the
whole dataset has 178,410 observations and about 40 variables), just to
illustrate what I mean.
These are the codes I am using:
In this simplified version:
-codebook id if mean_var1 != 11- counts both agents (408 in my dataset).
-codebook id if mean_var1 != 11 & (var1 == 10/var2 | var1 == 11/var2)-
counts 1 agent (id1) (397 in my dataset).
But -codebook id if mean_var1 != 11 & !(var1 == 10/var2 | var1 == 11/var2)-
also counts both agents. The reason is because -(var1 == 10/var2 | var1 ==
11/var2)- focuses on any value of var1 equal to 10 or 11 if var2 == 1 (ie,
if startdate == date). Nevertheless, -!(var1 == 10/var2 | var1 == 11/var2)-
refers to any observation where var1 and var2 are not equal to 10 or 11
regardless the value of var2. Therefore, observations 1, 2 and 4 for id1 and
5-8 for id2 are taken into account, ie, both agents are counted.
What I want to count is agents (i) whose mean_var is not equal to 11, (ii)
and have no observation in the date of the startdate (eg, for id2, startdate
= 192, but there is no observation for that date). Please, note that the
latter requirement is not having a missing value when startdate == date, but
that there is no observation.
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 12:31
Para: [email protected]
Asunto: Re: st: Counting firms in a panel dataset
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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