Cluster

A part of a sample constituted of statistical units that were grouped together because of a shared characteristic, usually a geographical feature, such as: individuals from the same household. A cluster survey is a special case of the two-stage survey in which statistical units are grouped into sub-groups called clusters. Clusters are then drawn at random, and all the units of each cluster are included in the sample. The Médiamat panel is one example of a cluster survey: all individuals aged 4 years and over from selected households are included in the sample.