قارن الطرق

	أخذ العينات النظري المستند إلى المجال	أخذ العينات ذو التباين الأقصى
المجال	منهجية المسح	منهجية المسح
العائلة	Process / pipeline	Process / pipeline
سنة النشأة	1967	1985 (Lincoln & Guba); elaborated 1990–2002 (Patton)
صاحب الطريقة	Barney G. Glaser and Anselm L. Strauss	Lincoln & Guba; systematised by Michael Quinn Patton
النوع	Qualitative iterative sampling strategy	Purposive qualitative sampling strategy
المصدر التأسيسي	Glaser, B. G., & Strauss, A. L. (1967). The Discovery of Grounded Theory: Strategies for Qualitative Research. Aldine. ISBN: 978-0202302607	Patton, M. Q. (2002). Qualitative Research and Evaluation Methods (3rd ed.). Sage. Chapter 5: Purposeful Sampling. ISBN: 978-0761919711
الأسماء البديلة	field theoretical sampling, in-situ theoretical sampling, fieldwork-driven theoretical sampling, grounded field sampling	maximum variation sampling, maximum diversity sampling, MVS, heterogeneous sampling
ذات صلة	3	5
الملخص	Field-based theoretical sampling is an iterative qualitative sampling strategy in which decisions about whom to observe or interview next are made during active fieldwork, guided by emerging theoretical insights from the data already collected. Rooted in Glaser and Strauss's grounded theory, it extends theoretical sampling into naturalistic, in-situ field settings — ethnographic sites, clinical environments, organizational contexts — where data collection and analysis proceed simultaneously.	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.