Dear FreeSurfer experts,
I have a longitudinal design with 3 groups and 3 time points. For one group the intervention did not work so for now I would like to look at 2 groups only. Can I do this with the Longitudinal Two Stage Model by looking at the spc from tp1 to tp2 and then looking at the spc from tp2 to tp3?
Are there statistical reasons that forbid this procedure of comparing the change across time between groups?
Thanks for your help! Clara