Which sampling method uses deliberate selection of participants based on predefined researcher criteria?

• A. Convenience sampling
• B. Quota sampling
• C. Snowball sampling
• D. Purposive sampling

Answer: (D)

Purposive sampling involves deliberately selecting individuals who meet predefined criteria set by the researcher. This non-random approach is used when the study needs insight from a specific subset of people—such as experts, patients with a particular condition, or individuals exhibiting a certain behavior—to deeply understand that phenomenon. Because participants are chosen for specific characteristics, the sample is informative for the research question but not designed to be representative of the entire population, so statistical generalization isn’t the goal. This contrasts with convenience sampling, which just uses readily available participants; quota sampling, which fills predefined subgroup quotas without targeting particular individuals; and snowball sampling, which relies on current participants to recruit others. In scenarios where the goal is to study people who meet specific criteria, purposive sampling is the most appropriate approach.