snowballing

Snowballing is a term used in multiple disciplines with related but distinct meanings. In its broad sense, it denotes a process in which a small initial input or event grows through successive additions, often in a self-reinforcing way.

Snowball sampling: A non-probability sampling method used to study hard-to-reach or stigmatized populations. Researchers begin with a few individuals who meet the criteria, who then refer others, and those referred individuals refer still more participants. The method can generate samples quickly and with relatively low cost, but may introduce bias and limit generalizability.

Snowballing in literature searching or systematic reviews: A technique for identifying additional relevant studies by examining the references of included papers (backward snowballing) and by identifying works that cite the included papers (forward snowballing). Used in combination with database searches to improve comprehensiveness and reduce missed studies.

Snowball effect: A broad metaphor used across social sciences and economics to describe how small beginnings can trigger a chain reaction leading to disproportionately large outcomes, such as viral spread, accumulation of debts, or rapid policy or adoption cascades.

Other uses: In slang, snowballing can refer to a sexual practice involving the exchange of saliva between partners. This usage is informal and varies by context and culture.