Purposive sampling, also known as judgmental sampling or selective sampling, is a non-probability sampling method where the researcher selects individuals or units for the sample based on specific criteria or characteristics that are relevant to the research objectives. The selection is purposeful and intentional, aiming to include participants who possess the desired qualities or attributes.
Here are some key characteristics and considerations of purposive sampling:
1. Researcher's judgment: Purposive sampling relies on the researcher's judgment and expertise in selecting participants who are most suitable for the research objectives. The researcher uses their knowledge and understanding of the population to handpick individuals or units that will provide valuable insights or represent specific characteristics.
2. Specific criteria: The selection of participants in purposive sampling is guided by predetermined criteria or characteristics that align with the research objectives. The criteria could be related to expertise, experience, unique perspectives, or specific attributes relevant to the study.
3. Heterogeneity and diversity: Purposive sampling allows for the intentional inclusion of participants who represent a diverse range of perspectives, experiences, or characteristics. The goal is to capture a broad spectrum of information and viewpoints to enrich the research findings.
4. Limited generalizability: Purposive sampling does not aim for statistical representativeness of the population, and the findings may not be generalizable to the broader population. The focus is on depth of understanding rather than making population-level inferences.
Purposive sampling is commonly used in qualitative research, case studies, and exploratory research where the researcher seeks in-depth insights, unique perspectives, or specialized knowledge. It can be particularly valuable when studying specific subgroups or when the research aims to explore specific characteristics or phenomena within a population.
However, it is important to acknowledge the limitations of purposive sampling, such as potential researcher bias and the lack of statistical representativeness. Researchers should clearly justify their selection criteria, document the sampling process, and interpret the findings within the context of the purposive sample.
