Purposeful sampling is a common method in qualitative research, used to select participants based on specific characteristics, experiences, or criteria. It is often used to identify current concepts, standards, and social issues, and to develop insight into study questions. Purposeful sampling is advantageous because it requires fewer resources and time compared to traditional methods. It is often cited in systematic reviews and used to evaluate questions of interest to various stakeholders. However, it faces challenges, such as publication bias due to its similarity to convenience sampling. To ensure validity, researchers must avoid outcome biases and overinterpretation of results. A key aspect of purposeful sampling is defining a clear study objective with both independent and dependent variables. Studies with multiple objectives should be avoided to prevent confounding. Two main forms of purposeful sampling are random and subjective. Random sampling involves random selection of participants, making the sample representative of the target population. Subjective sampling, on the other hand, uses non-random methods and is used to find divergent information among participants. Findings from subjective sampling are limited to the sample participants. Stratified and cell sampling are types of purposeful sampling that involve selecting specific groups, such as age groups or disaster victims. These methods require attention to inclusion and exclusion criteria. Quota sampling involves selecting specific categories and numbers of participants before recruitment. Snowball sampling, which uses initial participants to recruit more, is discouraged due to high selection bias. Convenience sampling is often mislabeled as purposeful sampling and is associated with low validity and bias. When using purposeful sampling, it is important to define and report recruitment methods, inclusion/exclusion criteria, and sample characteristics. The sample should reflect the target population's characteristics. In summary, purposeful sampling has two main forms: random and subjective. Random sampling findings are transferable to the target population, while subjective sampling findings are limited to the sample participants. Each form has specific applications for different research objectives.Purposeful sampling is a common method in qualitative research, used to select participants based on specific characteristics, experiences, or criteria. It is often used to identify current concepts, standards, and social issues, and to develop insight into study questions. Purposeful sampling is advantageous because it requires fewer resources and time compared to traditional methods. It is often cited in systematic reviews and used to evaluate questions of interest to various stakeholders. However, it faces challenges, such as publication bias due to its similarity to convenience sampling. To ensure validity, researchers must avoid outcome biases and overinterpretation of results. A key aspect of purposeful sampling is defining a clear study objective with both independent and dependent variables. Studies with multiple objectives should be avoided to prevent confounding. Two main forms of purposeful sampling are random and subjective. Random sampling involves random selection of participants, making the sample representative of the target population. Subjective sampling, on the other hand, uses non-random methods and is used to find divergent information among participants. Findings from subjective sampling are limited to the sample participants. Stratified and cell sampling are types of purposeful sampling that involve selecting specific groups, such as age groups or disaster victims. These methods require attention to inclusion and exclusion criteria. Quota sampling involves selecting specific categories and numbers of participants before recruitment. Snowball sampling, which uses initial participants to recruit more, is discouraged due to high selection bias. Convenience sampling is often mislabeled as purposeful sampling and is associated with low validity and bias. When using purposeful sampling, it is important to define and report recruitment methods, inclusion/exclusion criteria, and sample characteristics. The sample should reflect the target population's characteristics. In summary, purposeful sampling has two main forms: random and subjective. Random sampling findings are transferable to the target population, while subjective sampling findings are limited to the sample participants. Each form has specific applications for different research objectives.