Purposive sampling is a research sampling method where participants are chosen based on specific characteristics relevant to the research question. Researchers deliberately select individuals who possess particular qualities or expertise. This contrasts with random sampling, where participants are chosen randomly.
Understanding Purposive Sampling
Purposive sampling, also known as judgmental sampling or selective sampling, is a non-probability sampling technique. This means that not every member of the population has an equal chance of being selected. Instead, the selection is driven by the researcher's judgment and the specific needs of the study.
Key Characteristics of Purposive Sampling:
- Intentional Selection: Participants are chosen based on pre-defined criteria directly related to the research objectives.
- Specific Characteristics: These criteria could include demographics, experiences, knowledge, or specific traits relevant to the study.
- Non-probability: The selection process is not random, thus limiting generalizability to the wider population. However, it offers rich, in-depth data about the specific group studied.
- Researcher Expertise: The researcher's knowledge and judgment are crucial in identifying suitable participants.
Types of Purposive Sampling:
Several variations exist within purposive sampling, each serving slightly different research purposes:
- Typical case sampling: Selecting participants who represent the average or typical characteristics of the population.
- Extreme case sampling: Choosing participants who represent extreme or unusual cases.
- Homogenous sampling: Selecting participants who share similar characteristics.
- Heterogenous sampling: Selecting participants with diverse characteristics to capture a wide range of perspectives.
- Critical case sampling: Selecting cases that are critical to understanding the phenomenon under study.
Example:
Imagine researching the experiences of female entrepreneurs in the tech industry. Purposive sampling would involve deliberately recruiting female entrepreneurs who fit specific criteria, such as years of experience, company size, or industry specialization. This targeted approach ensures rich data directly relevant to the research question.
Contrast with Convenience Sampling:
As noted in the reference, Purposive sampling refers to intentionally selecting participants based on their characteristics, knowledge, experiences, or some other criteria. This differs significantly from convenience sampling, where participants are selected based primarily on accessibility and ease of recruitment.
