I have an unbalanced panel dataset. I'd like to convert to a balanced panel dataset where the data for the missing years are zero. How do I do this in Stata? I'll use an example to illustrate my problem.
Dataset 1
Country id year foreign aid
1 1993 230
1 1994 130
2 1990 100
2 1994 120
There are 2 countries. Country 1 did not receive any aid for 1990,1991, and 1992. Country 2 did not receive aid for 1991, 1992 and 1993. I'd like each country to have data from 1990-1994, and for foreign aid=0 for the missing years.
The dataset I need for my analysis should look like
Dataset 2
Country id year foreign aid
1 1990 0
1 1991 0
1 1992 0
1 1993 230
1 1994 130
2 1990 100
2 1991 0
2 1992 0
2 1993 0
2 1994 120
This is what I tried.
Step 1: I created another dataset with only two columns; country id and year:
Dataset 3
Country id year
1 1990
1 1991
1 1992
1 1993
1 1994
2 1990
2 1991
2 1992
2 1993
2 1994
Step 2: I merged the two datasets (i.e., Dataset 1 and Dataset 3) using country id and year.
I thought the merge will generate a balanced panel with "null" values for the variable foreign aid, for the years for which the country did not receive any aid. I could then replace the "null" with zeros. However the merge did not produce the desired result-it just did not work.
Any suggestions? Is the merge command appropriate?
Thanks in advance.
Elizabeth Asiedu
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