Good Morning


I was hoping that you would be able to offer some advice and guidance for a problem I am having.

I am trying to compare 4 treatments (Placebo, A, B and C) that have been observed at 3 times (baseline, 6mths and 12mths). I am trying to answer the question around comparing the change for particular variables between 6mth and baseline, 12mth and Baseline and between 6 and 12 Mths.

My question that I am aiming to answer is:
Is there a difference in the differences in a given variable (Continuous) from baseline between the treatment groups? If so, which is providing the greatest benefit?

In the past when addressing change in a variable across time I have used GEEs however this was for a binary Placebo/treatment scenario. I am just a little stuck with the multiple treatments.

I appreciate the time you take to consider my questions.

Kind Regards
Sean