Two-stage sampling has commonly been used in surveys of households and individuals. The standard strategy is first to stratify the frame population, then determine a reasonable number of primary sampling units (PSUs) within each stratum, to choose some of these with probability proportional to size (first stage) and, finally, to draw sampled units randomly within each cluster (second stage).
Retrospective two-stage cluster sampling for mortality in Iraq
Seppo LaaksonenUniversity of Helsinki
Giles (2007) presents a summary of the debate that began as soon as Burnham et al. (2006) published their Iraq Mortality Survey (IMS) results in the British journal His article starts: