Computational issues might require forming much fewer computational units, such as creating ‘pseudo-cluster’ from random groupings of sample elements, and then random pairing of these ‘clusters’ to construct computational strata. Grouping of units and strata can help in preserving confidential nature of the data. Reducing the detail included in this manner would make unnecessary the suppression of information on sample structure as has been done in the microdata disseminated by Eurostat.