Hello - I have a sample of 60 units that need to be randomized to treatment and control (30 and 30). However, I have several subgroups I want to block on, such that the units within them are randomized within the subgroups. There should be .5 probability of randomization within each block. I would like an outcome roughly like this: Group1 (6 units): 3T, 3C Group2 (10 units): 5T, 5C Group3 (6 units): 3T, 3C Group4 (38 units): 19T, 19C I am not sure how to code for this. I was thinking of something along these lines, but this doesn't seem to be quite right: PROC SURVEYSELECT DATA=mysample method = sys rate = 0.5 seed = 11235813 out=OUTFILE outall; STRATA Group1 Group2 Group3 Group4; Run; DATA assignment; SET OUTFILE; SamplingWeight GT 0 THEN GROUP = 'TREATMENT'; SamplingWeight EQ 0 THEN GROUP = 'CONTROL'; RUN; A second question is how I should set up my data file to facilitate this. I currently have binary indicator variables for each subgroup. How do I write the code to ensure that only the 1s for a given subgroup are randomized within that block? I realize this is a complex question. I appreciate any suggestions. Thanks.
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