Сравнение на методи

	Целенасочено онлайн вземане на проби	Максимално вариативно подбиране	Снежинково извадково изследване
Област	Методология на проучванията	Методология на проучванията	Методология на проучванията
Семейство	Process / pipeline	Process / pipeline	Process / pipeline
Година на възникване	1990s–2000s (with growth of internet-based research)	1985 (Lincoln & Guba); elaborated 1990–2002 (Patton)	1961
Създател	Adaptation of purposive sampling (Patton, 1987) to online/digital research contexts	Lincoln & Guba; systematised by Michael Quinn Patton	Leo A. Goodman
Тип	Non-probability qualitative sampling	Purposive qualitative sampling strategy	Non-probability sampling technique
Основополагащ източник	Patton, M. Q. (2002). Qualitative Research and Evaluation Methods (3rd ed.). Sage Publications. ISBN: 978-0761919711	Patton, M. Q. (2002). Qualitative Research and Evaluation Methods (3rd ed.). Sage. Chapter 5: Purposeful Sampling. ISBN: 978-0761919711	Goodman, L. A. (1961). Snowball sampling. Annals of Mathematical Statistics, 32(1), 148–170.
Други названия	internet-based purposive sampling, web purposive sampling, online criterion-based sampling, digital purposive sampling	maximum variation sampling, maximum diversity sampling, MVS, heterogeneous sampling	chain-referral sampling, network sampling, respondent-driven sampling, referral sampling
Свързани	3	5	3
Резюме	Online purposive sampling applies the logic of criterion-based participant selection to digital recruitment channels — including social media platforms, online communities, email lists, and research recruitment websites. Researchers intentionally seek individuals who possess the characteristics, experiences, or expertise directly relevant to the research question, using internet-based tools to locate and screen them. The method preserves the defining feature of purposive sampling — deliberate selection based on fitness for purpose — while leveraging the reach and accessibility of online environments.	Maximum variation sampling is a purposive qualitative sampling strategy in which the researcher deliberately selects cases that span the widest possible range of variation on dimensions central to the study. The goal is not statistical representation but the identification of common patterns that cut across diverse cases as well as the documentation of the unique ways each context shapes the phenomenon under investigation.	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.