I have 3 variables with repeated measures of the same subjects and I have missing values, what I want to do is to combine them in a single variable with the following criteria:
To create V4 use V3
If V3= 999 or 888 use values of V2
If V2= 999 or 888 use values of V1
Basically, I want the new variable to have the most recent value available.
Thank you for your help