Hello Arthur, I am not sure if this is exactly what I need, but I will look at it, thanks for your suggestion. Let me try to rephrase the question in a way that is more comprehensible: Suppose I have code as follows: %let groupa = a %let groupb = b %let groupc = c group1 = &groupa; group2 = &groupb; group3 = &groupc; Except what I want is that on each iteration of a larger loop, group1, group2, and group3 are randomly assigned to groupa, groupb, or groupc on each iteration (without replacement). So, perhaps the next iteration is then group1 = &groupc; group2 = &groupa; group3 = &groupb etc.. Hopefully that is more clear, thanks so much for your time!;
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