Probability Sample Methods

Cluster Sample

In Cluster Sampling, a population is divided into naturally occurring groups (or clusters). These types of groups generally have similar characteristics. For example, a population could be divided into clusters by county or zip codes. After the population is divided into clusters, some clusters are randomly selected. Then ALL subjects within those clusters are surveyed. Keep in mind, clusters are not like strata. Unlike strata, not all clusters are included in the sample.