Non-probability based sampling techniques refer to methods of selecting samples in which the elements of the population do not have a known or equal chance of being included in the sample. These techniques are widely used in research methodology when the population is difficult to define, when a sampling frame is not available, or when time and cost constraints make probability sampling impractical. In non-probability sampling, the selection of units depends largely on the judgment of the researcher or the convenience of accessibility. Although these techniques limit the generalizability of findings, they are useful in exploratory research, qualitative studies, and pilot investigations. One of the most commonly used non-probability sampling techniques is convenience sampling. In this method, the researcher selects respondents who are easily accessible and willing to participate. For example, students in a classroom or customers visiting a store may be chosen for a survey. Convenience sampling is simple, economical, and quick, but it is subject to significant bias because it may not represent the entire population accurately. Judgment or purposive sampling is another important technique. In this method, the researcher uses personal judgment to select respondents who are considered to be most representative or knowledgeable about the subject under study. This technique is particularly useful in case studies, expert interviews, and qualitative research where specific characteristics are required. The main advantage of purposive sampling is that it allows the researcher to focus on relevant cases; however, it may introduce subjective bias due to the researcher’s discretion. Quota sampling is a technique in which the population is divided into categories or strata based