مقایسهٔ روش‌ها

	نمونه‌گیری هدفمند	نمونه‌گیری حداکثر تنوع
حوزه	روش‌شناسی پیمایش	روش‌شناسی پیمایش
خانواده	Process / pipeline	Process / pipeline
سال پیدایش	Formalized ~1980–1990	1985 (Lincoln & Guba); elaborated 1990–2002 (Patton)
پدیدآور	Michael Quinn Patton (systematic articulation); roots in early qualitative inquiry	Lincoln & Guba; systematised by Michael Quinn Patton
نوع	Non-probability sampling strategy	Purposive qualitative sampling strategy
منبع بنیادین	Patton, M. Q. (1990). Qualitative Evaluation and Research Methods (2nd ed.). Sage. ISBN: 978-0803937796	Patton, M. Q. (2002). Qualitative Research and Evaluation Methods (3rd ed.). Sage. Chapter 5: Purposeful Sampling. ISBN: 978-0761919711
نام‌های دیگر	judgmental sampling, selective sampling, criterion-based sampling, purposeful sampling	maximum variation sampling, maximum diversity sampling, MVS, heterogeneous sampling
مرتبط	4	5
خلاصه	Purposive sampling is a non-probability strategy in which the researcher deliberately selects participants, documents, or cases that are information-rich with respect to the research question. Rather than drawing units at random, the researcher applies explicit criteria aligned with the study's purpose, maximising the depth and relevance of the data collected. It is the default sampling logic in most qualitative research designs and is also used in mixed-methods and applied evaluative work.	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.