I have a 2 x 2 Mixed ANOVA (2 independent groups assessed at 2 time points). I have a significant interaction, but my question is how can I assess the whether the changes in time over each group are driving the interaction?
I came across this post: Post-hoc for 2x2 mixed design ANOVA using SPSS
But I am not following as to how simply knowing there is an interaction tells you the nature of it. My initial thought was that beyond the simple main effects (group 1: time 1 vs time 2; group 2: time 1 vs time 2, time 1: group 1 vs group 2, time 2: group 1 vs group 2), I could do the difference between group 1 time 1 and 2 and difference in group 2 time 1 and 2 to assess if one group changed over time more than the other. However the post I linked suggests that this offers no new information.
Any insight would be greatly appreciated.
