very basic question

[bcdaniels]

I’m sorry to bother the list with a rather basic question, and though I am sure it's been answered, I couldn’t find an answer on the list or in the Stata FAQs.

My data look like this:

id poor70 poor71 poor72 poor73 poor74 observns |
|-----------------------------------------------------------------------|
1. | 1 0 0 0 0 1 1 |
2. | 2 0 0 1 1 . 1 |
3. | 2 0 0 1 1 . 2 |
4. | 3 1 1 . . . 1 |
5. | 3 1 1 . . . 2 |
|-----------------------------------------------------------------------|
6. | 4 1 1 1 1 0 1 |
7. | 4 1 1 1 1 0 2 |
8. | 4 1 1 1 1 0 3 |
9. | 4 1 1 1 1 0 4 |
10. | 5 0 1 1 0 . 1 |
|-----------------------------------------------------------------------|
11. | 5 0 1 1 0 . 2 |

Thus, I have 1 observation for each person for each year she is poor. What I would like to do is tell stata to treat each observation as a separate year for those the person is poor. So for person 1, for 1974, for person 2, one for 1973, one for 1974, etc. I would do this through do loops in SAS, but I am unsure how to do so in Stata. Any help is much appreciated.

Best,

Brendan

[Dave Airey]

I can't understand what you want your final data set to look like, from the sentences, "What I would like to do is tell stata to treat each observation as a separate year for those the person is poor. So for person 1, for 1974, for person 2, one for 1973, one for 1974, etc.". Please provide a small toy example.

[Sergiy Radyakin]

Brendan, see help for reshape.

[Joe Canner]

Brendan,

I agree with Dave and would also suggest possibly showing how you would solve this problem in SAS so that we can suggest a similar Stata solution.

In the meantime, here is my best guess as to what you want:

gen yearpoor=.
gen npoor=0
forvalues yr=70/74 {
  replace npoor=npoor+1 if poor`yr'==1
  replace yearpoor=`yr' if poor`yr'==1 & observns==npoor
}

This assumes that the observations for a person are in chronological order. If that is not the case or if that is irrelevant, then you will need to explain more.

Regards,
Joe

[Dave Airey]

If that is what is wanted then do something like Sergiy says:

clear
input id    poor70    poor71    poor72    poor73    poor74 observations
1    0    0    0    0    1    1
2    0    0    1    1    .    1
2    0    0    1    1    .    2
3    1    1    .    .    .    1
3    1    1    .    .    .    2
4    1    1    1    1    0    1
4    1    1    1    1    0    2
4    1    1    1    1    0    3
4    1    1    1    1    0    4
5    0    1    1    0    .    1
5    0    1    1    0    .    2
end

duplicates report id poor*
duplicates drop id poor*, force
drop observations
reshape long poor, i(id) j(year)
bysort id: egen observations = total(poor)

list, sepby(id)

[bcdaniels]

Thanks, all. I'm sorry for being unclear. I absolutely was. Reshape is almost certainly what I need. Cheers.

[Roberto Ferrer]

Brendan,

Please provide more informative titles for future questions.