Snowball sampling is a non-probability sampling method used by researchers to gather a sample for research studies, particularly when the population of interest is difficult to reach or identify, such as in studies of marginalised groups or hidden populations. In this method, researchers begin by identifying a small number of individuals who meet the study criteria and who are willing to participate. These initial participants are then asked to recruit acquaintances, friends, or other individuals from their own social networks who also fit the study's criteria, and this process continues, with each new participant potentially leading to more participants, much like a snowball rolling down a hill and gathering more snow. While snowball sampling can be effective in reaching hard-to-find populations, it may not result in a sample that is representative of the entire population, as participants are recruited through existing social networks, which may introduce certain biases.