Snowball Sampling

> In [sociology](https://en.wikipedia.org/wiki/Sociology) and [statistics](https://en.wikipedia.org/wiki/Statistics) research, snowball sampling[[1]](https://en.wikipedia.org/wiki/Snowball_sampling#cite_note-1) (or chain sampling, chain-referral sampling, referral sampling[[2]](https://en.wikipedia.org/wiki/Snowball_sampling#cite_note-2)[[3]](https://en.wikipedia.org/wiki/Snowball_sampling#cite_note-3)) is a [nonprobability sampling](https://en.wikipedia.org/wiki/Nonprobability_sampling) technique where existing study subjects recruit future subjects from among their acquaintances.

From https://en.wikipedia.org/wiki/Snowball_sampling

The issue contains only a definition of snowball sampling and a Wikipedia source; no file, test, entry point, requested change, or completion condition is named. First clarify whether this is intended as survey content and where it belongs in the YAML configurations. Work is not ready to start until the expected change and done criteria are agreed.

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