Final answer:
A snowball or chain sampling strategy is a non-random sampling method used in qualitative research, where initial participants recruit others from their social networks, helping researchers access hard-to-reach populations.
Step-by-step explanation:
What is a snowball or chain sampling strategy commonly used with purposive sampling? This question refers to a non-random sampling technique used in qualitative research. Snowball sampling, also known as chain referral sampling, is a method where existing study subjects recruit future subjects from among their acquaintances. This sampling strategy is especially useful for reaching populations that are difficult to access or are hidden. Researchers rely on the initial subjects to utilize their networks to identify other potential participants. This approach proves beneficial when the researcher's direct contact with potential participants is limited and when subjects can help in reaching out to their peers to support the study's aims.
Snowball sampling starts with a small group of participants who then use their social networks to recommend other participants. For example, to study an issue within a specific subculture or community, a researcher might start with a few key members who then refer others, growing the sample size like a snowball rolling downhill. Purposive sampling involves selecting participants based on specific characteristics or criteria set by the researcher, which means that not just anyone can participate, but those who are thought to be most beneficial to understanding the issue under investigation.