Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.

# st: Re: Making Cohorts

 From ajjee To statalist@hsphsun2.harvard.edu Subject st: Re: Making Cohorts Date Thu, 28 Oct 2010 03:30:45 -0700 (PDT)

```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
>
> 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
> --------------------------
>
>
>
>
> *
> *   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/
>
>

--
View this message in context: http://statalist.1588530.n2.nabble.com/Making-Cohorts-tp5681938p5682068.html
Sent from the Statalist mailing list archive at Nabble.com.

*
*   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/
```