[cem] creating blocks for randomized experiments

Hi, I was wondering if I could use coarsened exact matching (CEM) to create the following type of blocks/strata for a randomized experiment: 1st stage: block 50 schools into pairs (25 pairs total), randomization would take place in each pair 2nd stage: Take the students in each of the above schools (say there are 60 students in each school) and stratify them into triples as well, randomization would take place within each triple (assigned to treatment A, treatment B, and control). I have read for example that the cem command in Stata can create blocks for a randomized experiment, but I am not sure if it can create matched pairs and triples as in the above situation or not, since CEM may create different size blocks/strata according to the variables and degree of coarsening one chooses, rather than creating pairs/triples per say -- is there a way to actually create pairs/triples using CEM or do I have to additionally rely on another matching method (say using some distance measure) to create pairs/triples? And is further creating pairs/triples (beyond the blocks from cem) necessarily helpful in reducing bias and increasing power? Thank you so much in advance for your help, Prashant - cem Mailing List, served by Harvard-MIT Data Center Send messages: cem(a)lists.gking.harvard.edu [un]subscribe Options: http://lists.gking.harvard.edu/?info=cem More information on cem: http://gking.harvard.edu/cem