What is the main principle behind snowball sampling?

The principle behind snowball sampling is rooted in the use of existing participants to identify and recruit additional participants. This method is particularly useful in populations that may be difficult to access or identify through traditional sampling methods. By leveraging referrals from current participants, researchers can tap into networks and communities that are often hidden or not easily reachable.

In snowball sampling, as one participant is engaged, they can refer other individuals who fit the study's criteria, effectively allowing the sample to "snowball" as more participants are brought into the study through these recommendations. This technique can be particularly valuable in fields such as social psychology, sociology, or any research involving marginalized or hard-to-reach populations, where participants may be more inclined to trust and engage with someone recommended by a peer rather than through random selection or formal recruitment strategies.