I've been trying to generate a randomization schedule for permuted-

block randomization schedule and am having no luck with PROC PLAN. I

did it manually before, but was hoping for simplification.

I am looking to assign patients in a randomized multi-site trial to

two treatments (1 and 2). The plan calls for permuted-block

randomization with 2, 4 and 6 patients per block. A condition is

imposed where within each block, equal number of patients gets

assigned to each group, e.g. 1,1,2,2 in the block of 4 or 1,1,2,2,1,2

in the block of 6.

First, each site gets assigned multiple of block orders first. There

are six possible combinations of the three block sizes and each

triplet is good to randomize 12 patients. Let's say that I need to

randomize 120 patients which means that I need 10 random 3-block-size

orders per site. I think I can figure out how to do this part in PROC

PLAN on my own.

Next, I need to randomly fill in the actual treatment assignment

within each block. There are only two orders for the block of two

(1,2 and 2,1), 6 permutations in the block of 4 etc. So if the first

random block-order is 2-4-6, I need to randomly pick 1,2 or 2,1 for

block of 2; 1122, 2211,1221, 2112, 1212, or 2121 for block of 4, etc.

Is there a way to fill these values into a neat table with Proc PLAN?