Dear colleagues,
we are conducting an observational, longitudinal study with 10 groups that were tested for four times over three years with a metric outcome parameter. The last test’s will be performed in Summer 2021, therefore we do not know everything about the final dataset yet.
The groups differ considerably in size and the drop out rate might be quite high. Thus, it is unlikely that we will be able to use parametric tests for statistical analysis.
Originally, we wanted to use a Mixed-Method-ANOVA to compare how the groups differed over time. Since we believe this is not going to work out, it is our plan to replace the Mixed-Method-ANOVA with a Generalized Linear Mixed Model. However, I find it quite hard to find good tutorials or books on this topic for SPSS. Do you have any suggestions? I would appreciate your help.
Kind regards,
Benedikt Hielscher