st: How do I create a calendar year variable by person id before reshaping to person-year dataset?

[Holly E Reed <Holly.Reed@qc.cuny.edu>]

Hi,

I am trying to create a person-year dataset for event history analysis. The dataset currently has one observation per person per year of their life, e.g.:

id     age    sex    birthyear
1       5        F       1995
1       5        F       1995
1       5        F       1995
1       5        F       1995
1       5        F       1995
2       3        M      1997
2       3        M      1997
2       3        M      1997

So person with id==1 is a 5-year old female born in 1995 and person with id==2 is a 3-year old male born in 1997. This is a simplified example to illustrate the dataset, as they are all adults and there are far more observations for each individual.

The problem is that I have age and birthyear variables, but I want to create a calendar year variable before reshaping the data to person-year data.  What is the easiest way to do this?  In other words, I want the dataset to look like this:

id     age    sex    birthyear    year
1       5        F       1995        1995
1       5        F       1995        1996
1       5        F       1995        1997
1       5        F       1995        1998
1       5        F       1995        1999
2       3        M      1997        1997
2       3        M      1997        1998
2       3        M      1997        1999

Thank you very much for any help you can give me!  
Holly

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