how to fill in missing values of age by individuals

[David Lu]

Hi all,

Here is an example:

individual value
1 .
1 21
2 51
2 .
2 .
3 .
3 15
3 .

How can we fill in missing values of age by individuals?

individual value
1 20
1 21
2 51
2 52
2 53
3 14
3 15
3 16

Thanks in advance,
David

[Nick Cox]

I trust that you have a time variable too, in which case ipolate surely applies. People get older at the rate of 1 year per year, which is wonderfully linear.

[David Lu]

I trust that you have a time variable too, in which case ipolate surely applies. People get older at the rate of 1 year per year, which is wonderfully linear.

Hi Nick,

Thanks for your reply. -ipolate- works but there are still some missing values cannot be filled. here is an example:

the command is
bysort individual: ipolate age year, gen(agen)

what's wrong with it?

Thanks,
David

[Nick Cox]

You want to extrapolate too, and you have to specify that with the epolate option, which is documented in the help.