Hello I had a question regarding comparison tests. Currently I'm working on comparing 3 cohorts (pre, treatment, post) but I want to compare each cohort based on different years for each cohort. There is a 5 year difference between each cohort so I want to compare year 2000 for group 1 and year 2005 for group 2 and year 2010 for group 3 in one comparison test. How would I be able to do this and how could I loop it for 10 consecutive years (as the data is longitudinal)?