sampling methods

Simple random sampling

Each item or individual in a population has an equal chance of being selected

Systematic sampling

A sample selected by listing a population sequentially, and choosing members at regular intervals

Stratified sampling

The population is divided into distinct sub-groups based on specific characteristics, and a random sample is taken from each group to ensure all groups are represented equally

Quota sampling

The researcher divides the population into categories, and selects a set number (quota) of people from each group to include in the sample

Cluster sampling

The population is divided into diverse clusters, and entire clusters are randomly selected for study

Convenience/self-selected sampling

The researcher selects individuals who are easiest to reach or most readily available

Snowball sampling

The researcher starts with a small group of people who meet the criteria, then those people refer others they know who fit the criteria, and the process continues as the sample grows. This is done when it’s hard to find participants to study.