Σύγκριση μεθόδων

	Δειγματοληψία Εκτός Κανόνος Βάσει Πεδίου	Δειγματοληψία Χιονοστιβάδας
Πεδίο	Μεθοδολογία Επισκοπήσεων	Μεθοδολογία Επισκοπήσεων
Οικογένεια	Process / pipeline	Process / pipeline
Έτος προέλευσης	1980s–1990s (purposive/deviant case sampling literature)	1961
Δημιουργός	Michael Quinn Patton; Yvonna Lincoln & Egon Guba	Leo A. Goodman
Τύπος	Purposive qualitative sampling strategy	Non-probability sampling technique
Θεμελιώδης πηγή	Patton, M. Q. (2002). Qualitative Research and Evaluation Methods (3rd ed.). Sage Publications. ISBN: 978-0761919711	Goodman, L. A. (1961). Snowball sampling. Annals of Mathematical Statistics, 32(1), 148–170.
Εναλλακτικές ονομασίες	field deviant case sampling, outlier case sampling in field research, extreme case sampling in fieldwork, in-situ deviant case sampling	chain-referral sampling, network sampling, respondent-driven sampling, referral sampling
Συναφείς	5	3
Σύνοψη	Field-based deviant case sampling is a purposive strategy that deliberately selects cases deviating markedly from an established pattern or norm, with data collected through direct fieldwork — observation, in-situ interviews, and ethnographic engagement — in the participants' natural settings. By studying outliers on-site, researchers gain contextually grounded insight into why and how certain cases diverge from the typical pattern.	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.