
Hi there I am using for the first time Mlwin and I need to fit a linear growth model to my data (i am also a beginner in this kind of analysis).
We are interested to analyse the variation between 3 time points (3 follow-ups) of alcohol use in our patients, in order to determine if we can predict relapse.
I manage to fit the basic model with 2 level (L1 follow-ups L2 subjects, as my variables change only between subjects) but when I add new terms in the model I get an error saying that my explanatory variables are different lengths(offs), which is true, they are different lengths.
So any advice on what should I do next?
Please help as I ma really stock!

MANY THANKS!!!