I have a question about restructuring my data. I have a data set that I want to restructure from wide to long. I have 2 variables that are measured at time points T1, T2, T3 and T5 (so 4 source variables per target variable). And 8 variables that are measured at time points T1, T4 and T5 (3 source variables per target variable). However, it is required to have the same number of source variables for each target variable. How can I solve this? I can add a blank T4 for the first 2 variables and a blank T2 and T3 for the other ones, but I think SPSS will see it then as missing values in the analysis. Any other options?

I would be very thankful if you could help me!