What is Cluster Sampling?

Definition: Cluster sampling is a statistical sampling technique used when the population cannot be defined as being homogenous, making random sampling from classifications possible.

What Does Cluster Sampling Mean?

What is the definition of cluster sampling? It’s a sampling method used when assorted groupings are naturally exhibited in a population, making random sampling from those groups possible. The use of the technique requires the division or classification of the population into groups, defined by their assorted characteristics or qualities. These groups are then called clusters.

Cluster sampling is commonly used for market research because of its ability to help account for the common interest of a larger population at a relatively lower cost. Larger companies may find interviewing all their customers as nearly impossible, but the classification of their customers into clusters will help them to randomly sample some clusters as primary data for the interview.

One very important factor to consider when using this sampling technique is that an element in the population can only be classified or assigned to a single cluster.


Let’s assume that you want to evaluate the earnings of airport staff in the United States. Since the US has about 5,200 airports, a decision is made to classify all 5,200 airports as clusters, where the employees of each airport represent a cluster. You can then use a simple random sampling technique to select 100 airports from your 5,200 clusters. The earnings of the employees in those 100 airports will represent the primary data for your study.

What you have ultimately done, is to save yourself time from evaluating the earnings of employees from all 5,200 airports. It will also cost you less to travel to all 5,200 airports than the selected 100.

The downside of this technique, however, is the automatic presence of a higher sampling error. Also, results may not be a true representation of the entire population.

Summary Definition

Define Cluster Samples: Cluster sampling means a method of surveying a population based on groups naturally occurring in a population.