Found a solution:
COMPUTE Date_flare_FU = 0.
FORMATS Date_flare_FU (DATE11).
VECTOR A = Disease_activity_T1 TO Disease_activity_T12.
VECTOR B = Date_T1 TO Date_T12.
LOOP #v = 1 TO 12.
DO IF (A(#v)=1).
COMPUTE Date_flare_FU = B(#v).
END loop IF (A(#v)=1).
I am looking for help! Maybe someone here knows the answer?
I want to make a new variable (in SPSS) Date_flare_FU (Date of a disease flare during follow up). This variable will be based on 12 follow up visits (Date_T1 tm Date_T12 -> date), during which disease activity is assessed...