You will have to make two decisions here: first, choose a total
number of administrative divisions (clusters) to include in
your sample, and then distribute the clusters between strata.
While budgetary considerations largely dictate the number
of administrative divisions you can sample, every stratum
must be represented. The fewer you choose, the fewer
places your researchers have to visit to conduct interviews,
which translates into lower expenses. However, as a general
rule, the fewer clusters you select, the less representative
your sample of the general population will be