change variable value

[HEB1]

Hi

my data looks like this:

ID YEAR "VARIABLE A"  

1    1995    0

 1    1996    0

1     1997     0

1     1998     0

1     1999     1

1      2000     1

1      2001      0

1     2002      0

2    1995      1

I want for the same ID, to change the value of "variable a" to 1 only for the obs that are shown bellow "variable a"=1.

That is, I want to get this:

ID YEAR "VARIABLE A"  

1    1995    0

 1    1996    0

1     1997     0

1     1998     0

1     1999     1

1      2000     1

1      2001      1

1     2002     1

2    1995      1

[Kurt_Bremser · Accepted solution]

If I assume your rule correctly, this will do it:

data have;
input id year var_a;
datalines;
1 1995 0
1 1996 0
1 1997 0
1 1998 0
1 1999 1
1 2000 1
1 2001 0
1 2002 0
2 1995 1
;

data want;
set have (rename=(var_a=_var_a));
by id;
retain var_a;
if first.id then var_a = _var_a;
var_a = max(_var_a,var_a);
drop _var_a;
run;

Note how example data is presented in a data step with datalines; do so yourself in the future.