st: Re: Making Cohorts

[ajjee <ajjee1@yahoo.com>]

Thanks for Reply.

But I am still confused about COHORT. When I create this by cohort=year-age,
now it gives me year of birth of each respondent. Now I want to group each
respondent in a unique cohort.  I'm quoting procedure from a paper

"Define C cohorts, which are groups of individuals sharing some common
characteristic like sex or date of birth. These groups are defined in such a
manner that each individual is a member of exactly one cohort, and remains a
member of this cohort for all periods. For example, a particular cohort may
consist of all male individuals born in 1945–1949."


Hope you will help.

Thanks and Regards,

ajjee



Maarten buis wrote:
> 
> --- ajjee wrote:
>> I have the following type of survey data
>>
>> Year: 1980 1981 1982
>> 
>> Countries: 1 2 3...........15
>> 
>> Waves 1980_1 1980_2 1981_1 1981_2 1982_1 1982_2
>>
>> variables: sex education age occupation .....
>> 
>> I want to make cohorts of this data for logit
>> analysis. Please help me how to make cohorts.
> 
> I am assuming you want birth cohorts. The year
> of birth is year in which the survey was held minus
> the age of the respondent at that time, so:
> 
> gen cohort = year - age
> 
> As you can see above you cannot add cohort, year
> and age to your model. They are a linear combination
> of one another: if you know two you automatically 
> know the third, so there is no additional information
> present in the third. This means that you have to make
> a decision which one of these three you choose to 
> leave out of your model.
> 
> Typically it is a good idea to rescale such a 
> variable to have the value 0 wihtin the observed
> range and a more reasonable unit, e.g. decades
> since 1950 instead of years since 0:
> 
> gen cohort2 = (cohort - 1950)/10
> 
> Hope this helps,
> Maarten
> 
> --------------------------
> Maarten L. Buis
> Institut fuer Soziologie
> Universitaet Tuebingen
> Wilhelmstrasse 36
> 72074 Tuebingen
> Germany
> 
> http://www.maartenbuis.nl
> --------------------------
> 
> 
>       
> 
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> 

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