Hello Statalisters,

I have the following data which gives the ID of the mother (newid), birth order of the child (bord) and year of birth of said child (yobch). I declared the data as an unbalanced panel by
Code:
xtset newid bord
. Data example below. I want to create a dummy variable = 1 (name polexposure) if mother had 2 or more children in 1975, 1976 or 1977 and 0 if the mother had all her children before 1975, or started pregnancy by 1977 or had only one child throughout the 1975-77 period. To be more detailed, in the data below mother with newid 10 has had 6 children, all born before 1975 so I want the value of polexposure value for this id to be zero but the value of polexposure for newid 13 == 1 since she had more than 2 kids before 1975 and her next child was born after 1975. Again, the variable would also be zero for women who had their first child after 1977, or had less than 2 kids in 1975-77.

Do I need to convert this to a woman-year panel or could I work with the data below. If the latter, how do I create this dummy?

The code I have so far is

Code:
gen polexposure = 0
replace polexposure = 1 if bord >=2 & yobch <= 1977
But this makes woman with newid 13 have some entries equal to zero and will be equal to 1 for newid 10 since she did have more than 3 kids before 1975.

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input float newid byte bord int yobchild
 1 1 1985
 1 2 1988
 2 1 1977
 2 2 1985
 2 3 1989
 2 4 1992
 3 1 1967
 3 2 1973
 3 3 1977
 4 1 1989
 5 1 1982
 5 2 1986
 5 3 1991
 6 1 1958
 6 2 1962
 6 3 1964
 7 1 1980
 7 2 1982
 7 3 1984
 7 4 1985
 7 5 1988
 8 1 1985
 8 2 1986
 8 3 1991
 9 1 1984
 9 2 1986
 9 3 1989
 9 4 1991
10 1 1961
10 2 1964
10 3 1965
10 4 1967
10 5 1970
10 6 1971
11 1 1991
12 1 1982
12 2 1985
12 3 1986
13 1 1961
13 2 1964
13 3 1967
13 4 1969
13 5 1971
13 6 1976
14 1 1988
14 2 1991
15 1 1983
16 1 1991
17 1 1986
17 2 1989
17 3 1992
18 1 1979
18 2 1982
18 3 1987
19 1 1965
20 1 1978
21 1 1979
21 2 1983
21 3 1986
22 1 1959
22 2 1960
22 3 1961
22 4 1962
22 5 1963
22 6 1964
22 7 1965
23 1 1984
23 2 1988
24 1 1981
24 2 1984
24 3 1988
25 1 1988
26 1 1983
26 2 1986
26 3 1989
27 1 1960
27 2 1962
27 3 1968
27 4 1971
27 5 1980
27 6 1982
28 1 1956
28 2 1959
28 3 1963
28 4 1966
28 5 1973
28 6 1978
29 1 1983
29 2 1984
29 3 1987
30 1 1981
30 2 1982
30 3 1985
30 4 1987
31 1 1967
31 2 1969
31 3 1970
31 4 1973
31 5 1974
32 1 1987
end