Сравнение на методи

	Снежинково извадково изследване	Извадка, базирана на респонденти (Respondent-Driven Sampling)
Област	Методология на проучванията	Методология на проучванията
Семейство	Process / pipeline	Process / pipeline
Година на възникване	1961	1997
Създател	Leo A. Goodman	Douglas Heckathorn
Тип	Non-probability sampling technique	Probabilistic chain-referral sampling design
Основополагащ източник	Goodman, L. A. (1961). Snowball sampling. Annals of Mathematical Statistics, 32(1), 148–170.	Heckathorn, D. D. (1997). Respondent-driven sampling: A new approach to the study of hidden populations. Social Problems, 44(2), 174–199.
Други названия	chain-referral sampling, network sampling, respondent-driven sampling, referral sampling	Chain-Referral Sampling, Peer-Referral Sampling, Network-Based Sampling, Katılımcı Güdümlü Örnekleme
Свързани	3	3
Резюме	Snowball sampling is a non-probability recruitment technique in which initial participants (seeds) refer the researcher to others who meet the study criteria, and those referrals in turn refer further participants. The sample grows incrementally — like a rolling snowball — until the required size or theoretical saturation is reached. It is the method of choice when a target population has no accessible sampling frame, such as undocumented migrants, illicit drug users, survivors of stigmatised experiences, or members of closed professional networks.	Respondent-Driven Sampling (RDS) is a probabilistic chain-referral method designed to reach hidden or hard-to-reach populations that lack a sampling frame. Introduced by sociologist Douglas Heckathorn in 1997, RDS combines snowball recruitment with mathematical weighting based on participants' personal network sizes, allowing researchers to generate population-level estimates even when no complete membership list exists.